diff --git a/config/alfresco/public-services-context.xml b/config/alfresco/public-services-context.xml
index 6427584fa1..30f41312df 100644
--- a/config/alfresco/public-services-context.xml
+++ b/config/alfresco/public-services-context.xml
@@ -1058,6 +1058,9 @@
         <property name="avmService">
             <ref bean="avmService"/>
         </property>
+        <property name="avmRepository">
+            <ref bean="avmRepository"/>
+        </property>
     </bean>
     
     <bean id="AVMSyncService_descriptor" parent="AlfrescoServiceDescriptor">
diff --git a/source/java/org/alfresco/repo/avm/AVMRepository.java b/source/java/org/alfresco/repo/avm/AVMRepository.java
index 51d94777b9..0f92e8aa58 100644
--- a/source/java/org/alfresco/repo/avm/AVMRepository.java
+++ b/source/java/org/alfresco/repo/avm/AVMRepository.java
@@ -105,8 +105,12 @@ public class AVMRepository
     {
         fLookupCount.set(1);
         String[] pathParts = SplitPath(path);
-        AVMStore rep = getAVMStoreByName(pathParts[0]);
-        return rep.createFile(pathParts[1], name);
+        AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
+        return store.createFile(pathParts[1], name);
     }
 
     /**
@@ -119,8 +123,12 @@ public class AVMRepository
     {
         fLookupCount.set(1);
         String[] pathParts = SplitPath(path);
-        AVMStore rep = getAVMStoreByName(pathParts[0]);
-        rep.createFile(pathParts[1], name, data);
+        AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
+        store.createFile(pathParts[1], name, data);
     }
     
     /**
@@ -132,8 +140,12 @@ public class AVMRepository
     {
         fLookupCount.set(1);
         String[] pathParts = SplitPath(path);
-        AVMStore rep = getAVMStoreByName(pathParts[0]);
-        rep.createDirectory(pathParts[1], name);
+        AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
+        store.createDirectory(pathParts[1], name);
     }
 
     /**
@@ -157,6 +169,10 @@ public class AVMRepository
         // We need the store to do anything so...
         String [] pathParts = SplitPath(parent.getPath());
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         DirectoryNode dir = (DirectoryNode)node;
         DirectoryNode child = null;
         if (dir instanceof LayeredDirectoryNode)
@@ -188,9 +204,12 @@ public class AVMRepository
         }
         fLookupCount.set(1);
         String[] pathParts = SplitPath(dstPath);
-        AVMStore rep = getAVMStoreByName(pathParts[0]);
-//        fSession.get().lock(rep, LockMode.UPGRADE);
-        rep.createLayeredDirectory(srcPath, pathParts[1], name);
+        AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
+        store.createLayeredDirectory(srcPath, pathParts[1], name);
     }
 
     /**
@@ -203,8 +222,12 @@ public class AVMRepository
     {
         fLookupCount.set(1);
         String[] pathParts = SplitPath(dstPath);
-        AVMStore rep = getAVMStoreByName(pathParts[0]);
-        rep.createLayeredFile(srcPath, pathParts[1], name);
+        AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
+        store.createLayeredFile(srcPath, pathParts[1], name);
     }
 
     /**
@@ -213,15 +236,10 @@ public class AVMRepository
      */
     public void createAVMStore(String name)
     {
-        try
+        if (getAVMStoreByName(name) != null)
         {
-            getAVMStoreByName(name);
             throw new AVMExistsException("AVMStore exists: " + name);
         }
-        catch (AVMNotFoundException anf)
-        {
-            // Do nothing.
-        }
         // Newing up the object causes it to be written to the db.
         @SuppressWarnings("unused") 
         AVMStore rep = new AVMStoreImpl(this, name);
@@ -246,12 +264,32 @@ public class AVMRepository
         fLookupCount.set(1);
         String [] pathParts = SplitPath(srcPath);
         AVMStore srcRepo = getAVMStoreByName(pathParts[0]);
+        if (srcRepo == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
+        if (version < 0)
+        {
+            version = srcRepo.createSnapshot();
+        }
         Lookup sPath = srcRepo.lookup(version, pathParts[1], false, false);
+        if (sPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         // Lookup the destination directory.
         fLookupCount.set(1);
         pathParts = SplitPath(dstPath);
         AVMStore dstRepo = getAVMStoreByName(pathParts[0]);
+        if (dstRepo == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         Lookup dPath = dstRepo.lookupDirectory(-1, pathParts[1], true);
+        if (dPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         DirectoryNode dirNode = (DirectoryNode)dPath.getCurrentNode();
         AVMNode srcNode = sPath.getCurrentNode();
         AVMNode dstNode = null;
@@ -291,8 +329,12 @@ public class AVMRepository
     {
         fLookupCount.set(1);
         String [] pathParts = SplitPath(path);
-        AVMStore rep = getAVMStoreByName(pathParts[0]);
-        return rep.getOutputStream(pathParts[1]);
+        AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
+        return store.getOutputStream(pathParts[1]);
     }
     
     /**
@@ -313,7 +355,15 @@ public class AVMRepository
         fLookupCount.set(1);
         String [] pathParts = SplitPath(srcPath);
         AVMStore srcRepo = getAVMStoreByName(pathParts[0]);
+        if (srcRepo == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         Lookup sPath = srcRepo.lookupDirectory(-1, pathParts[1], true);
+        if (sPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         DirectoryNode srcDir = (DirectoryNode)sPath.getCurrentNode();
         AVMNode srcNode = srcDir.lookupChild(sPath, srcName, -1, true, false);
         if (srcNode == null)
@@ -323,7 +373,15 @@ public class AVMRepository
         fLookupCount.set(1);
         pathParts = SplitPath(dstPath);
         AVMStore dstRepo = getAVMStoreByName(pathParts[0]);
+        if (dstRepo == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         Lookup dPath = dstRepo.lookupDirectory(-1, pathParts[1], true);
+        if (dPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         DirectoryNode dstDir = (DirectoryNode)dPath.getCurrentNode();
         AVMNode dstNode = dstDir.lookupChild(dPath, dstName, -1, true, false);
         if (dstNode != null)
@@ -425,8 +483,12 @@ public class AVMRepository
     {
         fLookupCount.set(1);
         String [] pathParts = SplitPath(dirPath);
-        AVMStore repo = getAVMStoreByName(pathParts[0]);
-        repo.uncover(pathParts[1], name);
+        AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
+        store.uncover(pathParts[1], name);
     }
 
     /**
@@ -439,8 +501,12 @@ public class AVMRepository
         List<Integer> result = new ArrayList<Integer>();
         for (String repName : repositories)
         {
-            AVMStore repo = getAVMStoreByName(repName);
-            result.add(repo.createSnapshot());
+            AVMStore store = getAVMStoreByName(repName);
+            if (store == null)
+            {
+                throw new AVMNotFoundException("Store not found.");
+            }
+            result.add(store.createSnapshot());
         }
         return result;
     }
@@ -453,6 +519,10 @@ public class AVMRepository
     public int createSnapshot(String storeName)
     {
         AVMStore store = getAVMStoreByName(storeName);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         return store.createSnapshot();
     }
 
@@ -466,6 +536,10 @@ public class AVMRepository
         fLookupCount.set(1);
         String [] pathParts = SplitPath(path);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }        
         store.removeNode(pathParts[1], name);
     }
 
@@ -478,6 +552,10 @@ public class AVMRepository
     public void purgeAVMStore(String name)
     {
         AVMStore store = getAVMStoreByName(name);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         AVMNode root = store.getRoot();
         root.setIsRoot(false);
         VersionRootDAO vrDAO = AVMContext.fgInstance.fVersionRootDAO;
@@ -505,6 +583,10 @@ public class AVMRepository
     public void purgeVersion(String name, int version)
     {
         AVMStore store = getAVMStoreByName(name);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         store.purgeVersion(version);
     }
 
@@ -519,6 +601,10 @@ public class AVMRepository
         fLookupCount.set(1);
         String [] pathParts = SplitPath(path);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         return store.getInputStream(version, pathParts[1]);
     }
 
@@ -535,6 +621,10 @@ public class AVMRepository
         fLookupCount.set(1);
         String [] pathParts = SplitPath(path);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         return store.getListing(version, pathParts[1], includeDeleted);
     }
 
@@ -550,6 +640,10 @@ public class AVMRepository
         fLookupCount.set(1);
         String [] pathParts = SplitPath(path);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         return store.getListingDirect(version, pathParts[1], includeDeleted);
     }
     
@@ -612,6 +706,10 @@ public class AVMRepository
         fLookupCount.set(1);
         String [] pathParts = SplitPath(path);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         return store.getDeleted(version, pathParts[1]);
     }
     
@@ -639,6 +737,10 @@ public class AVMRepository
     public AVMStoreDescriptor getAVMStore(String name)
     {
         AVMStore store = getAVMStoreByName(name);
+        if (store == null)
+        {
+            return null;
+        }
         return store.getDescriptor();
     }
     
@@ -650,6 +752,10 @@ public class AVMRepository
     public List<VersionDescriptor> getAVMStoreVersions(String name)
     {
         AVMStore store = getAVMStoreByName(name);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         return store.getVersions();
     }
 
@@ -664,6 +770,10 @@ public class AVMRepository
     public List<VersionDescriptor> getAVMStoreVersions(String name, Date from, Date to)
     {
         AVMStore store = getAVMStoreByName(name);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         return store.getVersions(from, to);
     }
     
@@ -696,6 +806,10 @@ public class AVMRepository
         fLookupCount.set(1);
         String [] pathParts = SplitPath(path);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         return store.getIndirectionPath(version, pathParts[1]);
     }
 
@@ -707,6 +821,10 @@ public class AVMRepository
     public int getLatestVersionID(String name)
     {
         AVMStore store = getAVMStoreByName(name);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         return store.getNextVersionID();
     }
     
@@ -717,12 +835,7 @@ public class AVMRepository
      */
     private AVMStore getAVMStoreByName(String name)
     {
-        AVMStore store = AVMContext.fgInstance.fAVMStoreDAO.getByName(name);
-        if (store == null)
-        {
-            throw new AVMNotFoundException("AVMStore not found: " + name);
-        }
-        return store;
+        return AVMContext.fgInstance.fAVMStoreDAO.getByName(name);
     }
 
     /**
@@ -768,8 +881,11 @@ public class AVMRepository
             }
             String [] pathParts = SplitPath(path);
             AVMStore store = getAVMStoreByName(pathParts[0]);
-            Lookup result = store.lookup(version, pathParts[1], false, includeDeleted);
-            return result;
+            if (store == null)
+            {
+                return null;
+            }
+            return store.lookup(version, pathParts[1], false, includeDeleted);
         }
         finally
         {
@@ -780,6 +896,7 @@ public class AVMRepository
         }
     }
     
+    // TODO This should really return null for not found.
     /**
      * Lookup a descriptor from a directory descriptor.
      * @param dir The directory descriptor.
@@ -814,7 +931,15 @@ public class AVMRepository
         fLookupCount.set(1);
         String [] pathParts = SplitPath(path);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         Lookup lookup = store.lookup(version, pathParts[1], false, false);
+        if (lookup == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         return new LayeringDescriptor(!lookup.getDirectlyContained(),
                                       lookup.getAVMStore().getDescriptor(),
                                       lookup.getFinalStore().getDescriptor());
@@ -834,6 +959,10 @@ public class AVMRepository
         }
         String [] pathParts = SplitPath(path);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            return null;
+        }
         return store.lookupDirectory(version, pathParts[1], false);
     }
 
@@ -861,6 +990,10 @@ public class AVMRepository
         fLookupCount.set(1);
         String[] pathParts = SplitPath(path);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         store.makePrimary(pathParts[1]);
     }
 
@@ -874,6 +1007,10 @@ public class AVMRepository
         fLookupCount.set(1);
         String[] pathParts = SplitPath(path);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         store.retargetLayeredDirectory(pathParts[1], target);
     }
     
@@ -918,6 +1055,10 @@ public class AVMRepository
         fLookupCount.set(1);
         String[] pathParts = SplitPath(path);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         store.setOpacity(pathParts[1], opacity);
     }
         
@@ -932,6 +1073,10 @@ public class AVMRepository
         fLookupCount.set(1);
         String [] pathParts = SplitPath(path);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         store.setNodeProperty(pathParts[1], name, value);
     }
     
@@ -945,6 +1090,10 @@ public class AVMRepository
         fLookupCount.set(1);
         String [] pathParts = SplitPath(path);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         store.setNodeProperties(pathParts[1], properties);
     }
     
@@ -960,6 +1109,10 @@ public class AVMRepository
         fLookupCount.set(1);
         String [] pathParts = SplitPath(path);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         return store.getNodeProperty(version, pathParts[1], name);
     }
     
@@ -974,6 +1127,10 @@ public class AVMRepository
         fLookupCount.set(1);
         String [] pathParts = SplitPath(path);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         return store.getNodeProperties(version, pathParts[1]);
     }
     
@@ -987,6 +1144,10 @@ public class AVMRepository
         fLookupCount.set(1);
         String [] pathParts = SplitPath(path);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         store.deleteNodeProperty(pathParts[1], name);
     }
 
@@ -999,6 +1160,10 @@ public class AVMRepository
         fLookupCount.set(1);
         String [] pathParts = SplitPath(path);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         store.deleteNodeProperties(pathParts[1]);
     }
     
@@ -1010,7 +1175,12 @@ public class AVMRepository
      */
     public void setStoreProperty(String store, QName name, PropertyValue value)
     {
-        getAVMStoreByName(store).setProperty(name, value);
+        AVMStore st = getAVMStoreByName(store);
+        if (st == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
+        st.setProperty(name, value);
     }
     
     /**
@@ -1020,7 +1190,12 @@ public class AVMRepository
      */
     public void setStoreProperties(String store, Map<QName, PropertyValue> props)
     {
-        getAVMStoreByName(store).setProperties(props);
+        AVMStore st = getAVMStoreByName(store);
+        if (st == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
+        st.setProperties(props);
     }
     
     /**
@@ -1031,7 +1206,16 @@ public class AVMRepository
      */
     public PropertyValue getStoreProperty(String store, QName name)
     {
-        return getAVMStoreByName(store).getProperty(name);
+        if (store == null)
+        {
+            throw new AVMBadArgumentException("Null store name.");
+        }
+        AVMStore st = getAVMStoreByName(store);
+        if (st == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
+        return st.getProperty(name);
     }
     
     /**
@@ -1042,8 +1226,13 @@ public class AVMRepository
      */
     public Map<QName, PropertyValue> queryStorePropertyKey(String store, QName keyPattern)
     {
+        AVMStore st = getAVMStoreByName(store);
+        if (st == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         List<AVMStoreProperty> matches =
-            AVMContext.fgInstance.fAVMStorePropertyDAO.queryByKeyPattern(getAVMStoreByName(store),
+            AVMContext.fgInstance.fAVMStorePropertyDAO.queryByKeyPattern(st,
                                                                          keyPattern);
         Map<QName, PropertyValue> results = new HashMap<QName, PropertyValue>();
         for (AVMStoreProperty prop : matches)
@@ -1086,7 +1275,16 @@ public class AVMRepository
      */
     public Map<QName, PropertyValue> getStoreProperties(String store)
     {
-        return getAVMStoreByName(store).getProperties();
+        if (store == null)
+        {
+            throw new AVMBadArgumentException("Null store name.");
+        }
+        AVMStore st = getAVMStoreByName(store);
+        if (st == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
+        return st.getProperties();
     }
     
     /**
@@ -1096,17 +1294,12 @@ public class AVMRepository
      */
     public void deleteStoreProperty(String store, QName name)
     {
-        getAVMStoreByName(store).deleteProperty(name);
-    }
-    
-    /**
-     * Get the AVMStoreDescriptor for an AVMStore.
-     * @param name The name of the AVMStore.
-     * @return The descriptor.
-     */
-    public AVMStoreDescriptor getAVMStoreDescriptor(String name)
-    {
-        return getAVMStoreByName(name).getDescriptor();
+        AVMStore st = getAVMStoreByName(store);
+        if (st == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
+        st.deleteProperty(name);
     }
     
     /**
@@ -1179,6 +1372,10 @@ public class AVMRepository
         fLookupCount.set(1);
         String [] pathParts = SplitPath(path);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         return store.getContentDataForWrite(pathParts[1]);
     }
 
@@ -1192,6 +1389,10 @@ public class AVMRepository
         fLookupCount.set(1);
         String [] pathParts = SplitPath(path);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }        
         store.setContentData(pathParts[1], data);
     }
     
@@ -1214,6 +1415,10 @@ public class AVMRepository
         fLookupCount.set(1);
         String [] pathParts = SplitPath(path);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         store.addAspect(pathParts[1], aspectName);
     }
     
@@ -1228,6 +1433,10 @@ public class AVMRepository
         fLookupCount.set(1);
         String [] pathParts = SplitPath(path);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         return store.getAspects(version, pathParts[1]);
     }
     
@@ -1241,6 +1450,10 @@ public class AVMRepository
         fLookupCount.set(1);
         String [] pathParts = SplitPath(path);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         store.removeAspect(pathParts[1], aspectName);
     }
     
@@ -1256,6 +1469,10 @@ public class AVMRepository
         fLookupCount.set(1);
         String [] pathParts = SplitPath(path);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         return store.hasAspect(version, pathParts[1], aspectName);
     }
     
@@ -1269,6 +1486,10 @@ public class AVMRepository
         fLookupCount.set(1);
         String [] pathParts = SplitPath(path);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         store.setACL(pathParts[1], acl);
     }
     
@@ -1283,6 +1504,10 @@ public class AVMRepository
         fLookupCount.set(1);
         String [] pathParts = SplitPath(path);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         return store.getACL(version, pathParts[1]);
     }
     
@@ -1297,6 +1522,10 @@ public class AVMRepository
         fLookupCount.set(1);
         String [] pathParts = SplitPath(parentPath);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         store.link(pathParts[1], name, toLink);
     }
     
@@ -1353,8 +1582,16 @@ public class AVMRepository
         fLookupCount.set(1);
         String [] pathParts = SplitPath(path);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         // Just force a copy if needed by looking up in write mode.
         Lookup lPath = store.lookup(-1, pathParts[1], true, false);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         AVMNode node = lPath.getCurrentNode();
         return node.getDescriptor(lPath);
     }
diff --git a/source/java/org/alfresco/repo/avm/AVMServiceImpl.java b/source/java/org/alfresco/repo/avm/AVMServiceImpl.java
index 2f50eb4921..b45c72ec68 100644
--- a/source/java/org/alfresco/repo/avm/AVMServiceImpl.java
+++ b/source/java/org/alfresco/repo/avm/AVMServiceImpl.java
@@ -307,22 +307,6 @@ public class AVMServiceImpl implements AVMService
         fAVMRepository.createDirectory(path, name);
     }
 
-    /**
-     * Create a new directory, in an already copy on written node.
-     * This should only be used if you really know what you're doing.
-     * @param parent The parent node.
-     * @param name The name of the new directory.
-     * @return A descriptor for the newly created directory.
-     */
-    public AVMNodeDescriptor createDirectory(AVMNodeDescriptor parent, String name)
-    {
-        if (parent == null || name == null)
-        {
-            throw new AVMBadArgumentException("Illegal null argument.");
-        }
-        return fAVMRepository.createDirectory(parent, name);
-    }
-
     /**
      * Create a new layered file.  It must not exist.
      * @param srcPath The src path.  Ie the target for the layering.
@@ -511,6 +495,10 @@ public class AVMServiceImpl implements AVMService
         try
         {
             Lookup lookup = fAVMRepository.lookup(version, path, includeDeleted);
+            if (lookup == null)
+            {
+                return null;
+            }
             return lookup.getCurrentNode().getDescriptor(lookup);
         }
         catch (AVMNotFoundException e)
@@ -1082,42 +1070,6 @@ public class AVMServiceImpl implements AVMService
         fAVMRepository.link(parentPath, name, toLink);
     }
 
-    /**
-     * This is a more dangerous version of link, which assumes
-     * that copy on write has occurred for the parent node. This is
-     * an internal call. Don't use it if you don't know precisely
-     * what you are doing.
-     * @param parent The parent node.
-     * @param name The name to give the child.
-     * @param child The child node to link.
-     */
-    public void link(AVMNodeDescriptor parent, String name, AVMNodeDescriptor child)
-    {
-        if (parent == null || child == null)
-        {
-            throw new AVMBadArgumentException("Illegal Null Argument.");
-        }
-        fAVMRepository.link(parent, name, child);
-    }
-    
-    /**
-     * Flatten a direct child of a layered directory. This does
-     * the equivalent of removing the given child from the directory 
-     * and then doing an uncover. This routine makes many dangerous 
-     * assumptions and is only for use by AVMSyncService. Don't use it
-     * if you don't know precisely what you are doing.
-     * @param lDir The layered directory node.
-     * @param name The name to flatten.
-     */
-    public void flatten(AVMNodeDescriptor lDir, String name)
-    {
-        if (lDir == null || name == null)
-        {
-            throw new AVMBadArgumentException("Illegal Null Argument.");
-        }
-        fAVMRepository.flatten(lDir, name);
-    }
-
     /**
      * Force copy on write of a path.
      * @param path The path to force.
diff --git a/source/java/org/alfresco/repo/avm/AVMServiceTest.java b/source/java/org/alfresco/repo/avm/AVMServiceTest.java
index edd18d6d8d..6fe2d05006 100644
--- a/source/java/org/alfresco/repo/avm/AVMServiceTest.java
+++ b/source/java/org/alfresco/repo/avm/AVMServiceTest.java
@@ -59,6 +59,61 @@ import org.alfresco.service.transaction.TransactionService;
  */
 public class AVMServiceTest extends AVMServiceTestBase
 {
+    /**
+     * Test that an update forces a snapshot on the source.
+     */
+    public void testUpdateSnapshot()
+    {
+        try
+        {
+            setupBasicTree();
+            fService.createAVMStore("branch");
+            fService.createBranch(-1, "main:/", "branch:/", "branch");
+            // Modify some things in the branch.
+            fService.createFile("branch:/branch/a/b", "fing").close();
+            fService.getFileOutputStream("branch:/branch/a/b/c/foo").close();
+            fService.removeNode("branch:/branch/a/b/c", "bar");
+            List<AVMDifference> diffs =
+                fSyncService.compare(-1, "branch:/branch", -1, "main:/");
+            assertEquals(3, diffs.size());
+            // Now update.
+            fSyncService.update(diffs, false, false, false, false);
+            diffs = fSyncService.compare(-1, "branch:/branch", -1, "main:/");
+            assertEquals(0, diffs.size());
+            fService.getFileOutputStream("branch:/branch/a/b/fing").close();
+            assertTrue(fService.lookup(-1, "branch:/branch/a/b/fing").getId() !=
+                       fService.lookup(-1, "main:/a/b/fing").getId());
+        }
+        catch (Exception e)
+        {
+            e.printStackTrace(System.err);
+            fail();
+        }
+    }
+    
+    /**
+     * Test that branching forces a snapshot on the source repository.
+     */
+    public void testBranchSnapshot()
+    {
+        try
+        {
+            setupBasicTree();
+            fService.getFileOutputStream("main:/a/b/c/foo").close();
+            fService.createBranch(-1, "main:/a", "main:/", "abranch");
+            assertEquals(fService.lookup(-1, "main:/a/b/c/foo").getId(),
+                         fService.lookup(-1, "main:/abranch/b/c/foo").getId());
+            fService.getFileOutputStream("main:/a/b/c/foo").close();
+            assertTrue(fService.lookup(-1, "main:/a/b/c/foo").getId() !=
+                       fService.lookup(-1, "main:/abranch/b/c/foo").getId());
+        }
+        catch (Exception e)
+        {
+            e.printStackTrace(System.err);
+            fail();
+        }
+    }
+    
     /**
      * Test bulk update.
      */
diff --git a/source/java/org/alfresco/repo/avm/AVMStoreImpl.java b/source/java/org/alfresco/repo/avm/AVMStoreImpl.java
index 24503a6582..a331b2820b 100644
--- a/source/java/org/alfresco/repo/avm/AVMStoreImpl.java
+++ b/source/java/org/alfresco/repo/avm/AVMStoreImpl.java
@@ -141,7 +141,8 @@ public class AVMStoreImpl implements AVMStore, Serializable
         // If the root isn't new, we can't take a snapshot since nothing has changed.
         if (!fRoot.getIsNew())
         {
-            throw new AVMExistsException("Already snapshotted.");
+            // So we just return the most recent snapshot.
+            return AVMContext.fgInstance.fVersionRootDAO.getMaxVersionID(this);
         }
         // Clear out the new nodes.
         List<AVMNode> newInRep = AVMContext.fgInstance.fAVMNodeDAO.getNewInStore(this);
@@ -150,11 +151,16 @@ public class AVMStoreImpl implements AVMStore, Serializable
             newGuy.setStoreNew(null);
         }
         // Make up a new version record.
+        String user = AVMContext.fgInstance.getAuthenticationComponent().getCurrentUserName();
+        if (user == null)
+        {
+            user = AVMContext.fgInstance.getAuthenticationComponent().getSystemUserName();
+        }
         VersionRoot versionRoot = new VersionRootImpl(this,
                                                       fRoot,
                                                       fNextVersionID,
                                                       System.currentTimeMillis(),
-                                                      "britt");
+                                                      user);
         AVMContext.fgInstance.fVersionRootDAO.save(versionRoot);
         // Increment the version id.
         fNextVersionID++;
@@ -169,6 +175,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public void createDirectory(String path, String name)
     {
         Lookup lPath = lookupDirectory(-1, path, true);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         DirectoryNode dir = (DirectoryNode)lPath.getCurrentNode();
         if (dir.lookupChild(lPath, name, -1, true, false) != null)
         {
@@ -202,6 +212,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
                                        String name)
     {
         Lookup lPath = lookupDirectory(-1, dstPath, true);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         DirectoryNode dir = (DirectoryNode)lPath.getCurrentNode();
         if (dir.lookupChild(lPath, name, -1, true, false) != null)
         {
@@ -236,6 +250,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public OutputStream createFile(String path, String name)
     {
         Lookup lPath = lookupDirectory(-1, path, true);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         DirectoryNode dir = (DirectoryNode)lPath.getCurrentNode();
         if (dir.lookupChild(lPath, name, -1, true, false) != null)
         {
@@ -262,6 +280,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public void createFile(String path, String name, File data)
     {
         Lookup lPath = lookupDirectory(-1, path, true);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         DirectoryNode dir = (DirectoryNode)lPath.getCurrentNode();
         if (dir.lookupChild(lPath, name, -1, true, false) != null)
         {
@@ -288,6 +310,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public void createLayeredFile(String srcPath, String dstPath, String name)
     {
         Lookup lPath = lookupDirectory(-1, dstPath, true);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         DirectoryNode dir = (DirectoryNode)lPath.getCurrentNode();
         if (dir.lookupChild(lPath, name, -1, true, false) != null)
         {
@@ -354,6 +380,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
                                                            boolean includeDeleted)
     {
         Lookup lPath = lookupDirectory(version, path, false);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         DirectoryNode dir = (DirectoryNode)lPath.getCurrentNode();
         Map<String, AVMNode> listing = dir.getListing(lPath, includeDeleted);
         return translateListing(listing, lPath);
@@ -369,6 +399,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
                                                                  boolean includeDeleted)
     {
         Lookup lPath = lookupDirectory(version, path, false);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         DirectoryNode dir = (DirectoryNode)lPath.getCurrentNode();
         if (lPath.isLayered() && dir.getType() != AVMNodeType.LAYERED_DIRECTORY)
         {
@@ -407,6 +441,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public List<String> getDeleted(int version, String path)
     {
         Lookup lPath = lookupDirectory(version, path, false);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         DirectoryNode dir = (DirectoryNode)lPath.getCurrentNode();
         return dir.getDeletedNames();
     }
@@ -443,6 +481,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public void removeNode(String path, String name)
     {
         Lookup lPath = lookupDirectory(-1, path, true);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         DirectoryNode dir = (DirectoryNode)lPath.getCurrentNode();
         if (dir.lookupChild(lPath, name, -1, true, false) == null)
         {
@@ -460,6 +502,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public void uncover(String dirPath, String name)
     {
         Lookup lPath = lookup(-1, dirPath, true, false);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         AVMNode node = lPath.getCurrentNode();
         if (node.getType() != AVMNodeType.LAYERED_DIRECTORY)
         {
@@ -540,7 +586,7 @@ public class AVMStoreImpl implements AVMStore, Serializable
         Lookup result = new Lookup(this, fName);
         if (path.length() == 0)
         {
-            throw new AVMException("Invalid path: " + path);
+            return null;
         }
         while (path.startsWith("/"))
         {
@@ -576,13 +622,13 @@ public class AVMStoreImpl implements AVMStore, Serializable
             AVMNode child = dir.lookupChild(result, pathElements[i], version, write, includeDeleted);
             if (child == null)
             {
-                throw new AVMNotFoundException("Not found: " + pathElements[i]);
+                return null;
             }
             // Every element that is not the last needs to be a directory.
             if (child.getType() != AVMNodeType.PLAIN_DIRECTORY &&
                 child.getType() != AVMNodeType.LAYERED_DIRECTORY)
             {
-                throw new AVMNotFoundException("Not a directory: " + pathElements[i]);
+                return null;
             }
             result.add(child, pathElements[i], write);
             dir = (DirectoryNode)result.getCurrentNode();
@@ -592,7 +638,7 @@ public class AVMStoreImpl implements AVMStore, Serializable
                                         includeDeleted);
         if (child == null)
         {
-            throw new AVMNotFoundException("Not found: " + pathElements[pathElements.length - 1]);
+            return null;
         }
         result.add(child, pathElements[pathElements.length - 1], write);
         return result;
@@ -629,10 +675,14 @@ public class AVMStoreImpl implements AVMStore, Serializable
         // Just do a regular lookup and assert that the last element
         // is a directory.
         Lookup lPath = lookup(version, path, write, false);
+        if (lPath == null)
+        {
+            return null;
+        }
         if (lPath.getCurrentNode().getType() != AVMNodeType.PLAIN_DIRECTORY &&
             lPath.getCurrentNode().getType() != AVMNodeType.LAYERED_DIRECTORY)
         {
-            throw new AVMWrongTypeException("Not a directory: " + path);
+            return null;
         }
         return lPath;
     }
@@ -646,6 +696,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public String getIndirectionPath(int version, String path)
     {
         Lookup lPath = lookup(version, path, false, false);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         AVMNode node = lPath.getCurrentNode();
         if (node.getType() == AVMNodeType.LAYERED_DIRECTORY)
         {
@@ -665,7 +719,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public void makePrimary(String path)
     {
         Lookup lPath = lookupDirectory(-1, path, true);
-//        lPath.acquireLocks();
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         DirectoryNode dir = (DirectoryNode)lPath.getCurrentNode();
         if (!lPath.isLayered())
         {
@@ -683,7 +740,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public void retargetLayeredDirectory(String path, String target)
     {
         Lookup lPath = lookupDirectory(-1, path, true);
-//        lPath.acquireLocks();
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         DirectoryNode dir = (DirectoryNode)lPath.getCurrentNode();
         if (!lPath.isLayered())
         {
@@ -844,6 +904,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public void setOpacity(String path, boolean opacity)
     {
         Lookup lPath = lookup(-1, path, true, false);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         AVMNode node = lPath.getCurrentNode();
         if (!(node instanceof LayeredDirectoryNode))
         {
@@ -863,6 +927,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public void setNodeProperty(String path, QName name, PropertyValue value)
     {
         Lookup lPath = lookup(-1, path, true, false);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         AVMNode node = lPath.getCurrentNode();
         node.setProperty(name, value);
     }
@@ -875,6 +943,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public void setNodeProperties(String path, Map<QName, PropertyValue> properties)
     {
         Lookup lPath = lookup(-1, path, true, false);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         AVMNode node = lPath.getCurrentNode();
         node.setProperties(properties);
     }
@@ -889,6 +961,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public PropertyValue getNodeProperty(int version, String path, QName name)
     {
         Lookup lPath = lookup(version, path, false, false);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         AVMNode node = lPath.getCurrentNode();
         return node.getProperty(name);
     }
@@ -902,6 +978,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public Map<QName, PropertyValue> getNodeProperties(int version, String path)
     {
         Lookup lPath = lookup(version, path, false, false);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         AVMNode node = lPath.getCurrentNode();
         return node.getProperties();
     }
@@ -914,6 +994,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public void deleteNodeProperty(String path, QName name)
     {
         Lookup lPath = lookup(-1, path, true, false);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         AVMNode node = lPath.getCurrentNode();
         node.deleteProperty(name);
     }
@@ -925,6 +1009,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public void deleteNodeProperties(String path)
     {
         Lookup lPath = lookup(-1, path, true, false);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         AVMNode node = lPath.getCurrentNode();
         node.deleteProperties();
     }
@@ -999,6 +1087,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public ContentData getContentDataForRead(int version, String path)
     {
         Lookup lPath = lookup(version, path, false, false);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         AVMNode node = lPath.getCurrentNode();
         if (!(node instanceof FileNode))
         {
@@ -1015,6 +1107,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public ContentData getContentDataForWrite(String path)
     {
         Lookup lPath = lookup(-1, path, true, false);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         AVMNode node = lPath.getCurrentNode();
         if (!(node instanceof FileNode))
         {
@@ -1031,6 +1127,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public void setContentData(String path, ContentData data)
     {
         Lookup lPath = lookup(-1, path, true, false);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         AVMNode node = lPath.getCurrentNode();
         if (!(node instanceof FileNode))
         {
@@ -1047,6 +1147,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public void addAspect(String path, QName aspectName)
     {
         Lookup lPath = lookup(-1, path, true, false);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         AVMNode node = lPath.getCurrentNode();
         if (AVMContext.fgInstance.fAVMAspectNameDAO.exists(node, aspectName))
         {
@@ -1068,6 +1172,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public List<QName> getAspects(int version, String path)
     {
         Lookup lPath = lookup(version, path, false, false);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         AVMNode node = lPath.getCurrentNode();
         List<AVMAspectName> names = 
             AVMContext.fgInstance.fAVMAspectNameDAO.get(node);
@@ -1087,6 +1195,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public void removeAspect(String path, QName aspectName)
     {
         Lookup lPath = lookup(-1, path, true, false);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         AVMNode node = lPath.getCurrentNode();
         AVMContext.fgInstance.fAVMAspectNameDAO.delete(node, aspectName);
         AspectDefinition def = AVMContext.fgInstance.getDictionaryService().getAspect(aspectName);
@@ -1108,6 +1220,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public boolean hasAspect(int version, String path, QName aspectName)
     {
         Lookup lPath = lookup(version, path, false, false);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         AVMNode node = lPath.getCurrentNode();
         return AVMContext.fgInstance.fAVMAspectNameDAO.exists(node, aspectName);
     }
@@ -1120,6 +1236,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public void setACL(String path, DbAccessControlList acl)
     {
         Lookup lPath = lookup(-1, path, true, false);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         AVMNode node = lPath.getCurrentNode();
         node.setAcl(acl);
     }
@@ -1133,6 +1253,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public DbAccessControlList getACL(int version, String path)
     {
         Lookup lPath = lookup(version, path, false, false);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         return lPath.getCurrentNode().getAcl();
     }
     
@@ -1145,6 +1269,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public void link(String parentPath, String name, AVMNodeDescriptor toLink)
     {
         Lookup lPath = lookupDirectory(-1, parentPath, true);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         DirectoryNode dir = (DirectoryNode)lPath.getCurrentNode();
         dir.link(lPath, name, toLink);
     }
diff --git a/source/java/org/alfresco/repo/avm/AVMSyncServiceImpl.java b/source/java/org/alfresco/repo/avm/AVMSyncServiceImpl.java
index 863cf6d8c7..84a095cf23 100644
--- a/source/java/org/alfresco/repo/avm/AVMSyncServiceImpl.java
+++ b/source/java/org/alfresco/repo/avm/AVMSyncServiceImpl.java
@@ -46,6 +46,11 @@ public class AVMSyncServiceImpl implements AVMSyncService
      */
     private AVMService fAVMService;
 
+    /**
+     * The AVMRepository.
+     */
+    private AVMRepository fAVMRepository;
+    
     /**
      * Do nothing constructor.
      */
@@ -54,10 +59,7 @@ public class AVMSyncServiceImpl implements AVMSyncService
     }
 
     /**
-     * Set the AVM Service. For Spring. For now, at least,
-     * it's important to wire this using the unintercepted AVMServiceImpl,
-     * as AVMServiceImpl uses Runtime Exceptions for handling valid states
-     * that should not cause rollbacks.
+     * Set the AVM Service. For Spring. 
      * @param avmService The AVMService reference.
      */
     public void setAvmService(AVMService avmService)
@@ -65,6 +67,11 @@ public class AVMSyncServiceImpl implements AVMSyncService
         fAVMService = avmService;
     }
     
+    public void setAvmRepository(AVMRepository avmRepository)
+    {
+        fAVMRepository = avmRepository;
+    }
+    
     /**
      * Get a difference list between two corresponding node trees.
      * @param srcVersion The version id for the source tree.
@@ -280,7 +287,14 @@ public class AVMSyncServiceImpl implements AVMSyncService
             {
                 throw new AVMSyncException("Malformed AVMDifference.");
             }
-            AVMNodeDescriptor srcDesc = fAVMService.lookup(diff.getSourceVersion(),
+            int colonOff = diff.getSourcePath().indexOf(':');
+            if (colonOff == -1)
+            {
+                throw new AVMBadArgumentException("Invalid path.");
+            }
+            String storeName = diff.getSourcePath().substring(0, colonOff);
+            int version = fAVMService.createSnapshot(storeName);
+            AVMNodeDescriptor srcDesc = fAVMService.lookup(version,
                                                            diff.getSourcePath(), true);
             if (srcDesc == null)
             {
@@ -385,8 +399,6 @@ public class AVMSyncServiceImpl implements AVMSyncService
         fAVMService.link(parentPath, name, toLink);
     }
     
-    // TODO doesn't handle copies from non head nodes.
-    
     /**
      * Recursively copy a node into the given position.
      * @param parentPath The place to put it.
@@ -417,12 +429,12 @@ public class AVMSyncServiceImpl implements AVMSyncService
         // If it's a file or deleted simply link it in.
         if (toCopy.isFile() || toCopy.isDeleted() || toCopy.isPlainDirectory())
         {
-            fAVMService.link(parent, name, toCopy);
+            fAVMRepository.link(parent, name, toCopy);
             return;
         }
         // Otherwise make a directory in the target parent, and recursiveCopy all the source
         // children into it.
-        AVMNodeDescriptor newParentDesc = fAVMService.createDirectory(parent, name);
+        AVMNodeDescriptor newParentDesc = fAVMRepository.createDirectory(parent, name);
         fgLogger.error(newParentDesc);
         Map<String, AVMNodeDescriptor> children = 
             fAVMService.getDirectoryListing(toCopy, true);
@@ -613,14 +625,14 @@ public class AVMSyncServiceImpl implements AVMSyncService
             // We've found an identity so flatten it.
             if (topNode.getId() == bottomNode.getId())
             {
-                fAVMService.flatten(layer, name);
+                fAVMRepository.flatten(layer, name);
             }
             else
             {
                 // Otherwise recursively flatten the children.
                 if (flatten(topNode, bottomNode))
                 {
-                    fAVMService.flatten(layer, name);
+                    fAVMRepository.flatten(layer, name);
                 }
                 else
                 {
diff --git a/source/java/org/alfresco/repo/avm/LayeredDirectoryNodeImpl.java b/source/java/org/alfresco/repo/avm/LayeredDirectoryNodeImpl.java
index cb8badfdae..c9dff89bb9 100644
--- a/source/java/org/alfresco/repo/avm/LayeredDirectoryNodeImpl.java
+++ b/source/java/org/alfresco/repo/avm/LayeredDirectoryNodeImpl.java
@@ -25,7 +25,6 @@ import java.util.SortedMap;
 import java.util.TreeMap;
 
 import org.alfresco.service.cmr.avm.AVMBadArgumentException;
-import org.alfresco.service.cmr.avm.AVMCycleException;
 import org.alfresco.service.cmr.avm.AVMException;
 import org.alfresco.service.cmr.avm.AVMExistsException;
 import org.alfresco.service.cmr.avm.AVMNodeDescriptor;
@@ -316,18 +315,14 @@ class LayeredDirectoryNodeImpl extends DirectoryNodeImpl implements LayeredDirec
         }
         else
         {
-            try
+            Lookup lookup = AVMRepository.GetInstance().lookupDirectory(-1, getUnderlying(lPath));
+            if (lookup != null)
             {
-                Lookup lookup = AVMRepository.GetInstance().lookupDirectory(-1, getUnderlying(lPath));
                 DirectoryNode dir = (DirectoryNode)lookup.getCurrentNode();
                 listing = dir.getListing(lookup, includeDeleted);
             }
-            catch (AVMException re)
+            else
             {
-                if (re instanceof AVMCycleException)
-                {
-                    throw re;
-                }
                 // It's OK for an indirection to dangle.
                 listing = new HashMap<String, AVMNode>();
             }
@@ -406,9 +401,9 @@ class LayeredDirectoryNodeImpl extends DirectoryNodeImpl implements LayeredDirec
         // If we are not opaque, get the underlying base listing.
         if (!fOpacity)
         {
-            try
+            Lookup lookup = AVMRepository.GetInstance().lookupDirectory(-1, dir.getIndirection());
+            if (lookup != null)
             {
-                Lookup lookup = AVMRepository.GetInstance().lookupDirectory(-1, dir.getIndirection());
                 DirectoryNode dirNode = (DirectoryNode)lookup.getCurrentNode();
                 Map<String, AVMNode> listing = dirNode.getListing(lookup, includeDeleted);
                 for (String name : listing.keySet())
@@ -418,13 +413,6 @@ class LayeredDirectoryNodeImpl extends DirectoryNodeImpl implements LayeredDirec
                                                                     lookup.getCurrentIndirection()));
                 }
             }
-            catch (AVMException e)
-            {
-                if (e instanceof AVMCycleException)
-                {   
-                    throw e;
-                }
-            }
         }
         List<ChildEntry> children = AVMContext.fgInstance.fChildEntryDAO.getByParent(this);
         for (ChildEntry child : children)
@@ -489,20 +477,16 @@ class LayeredDirectoryNodeImpl extends DirectoryNodeImpl implements LayeredDirec
             return null;
         }
         // Not here so check our indirection.
-        try
+        Lookup lookup = AVMRepository.GetInstance().lookupDirectory(-1, getUnderlying(lPath));
+        if (lookup != null)
         {
-            Lookup lookup = AVMRepository.GetInstance().lookupDirectory(-1, getUnderlying(lPath));
             DirectoryNode dir = (DirectoryNode)lookup.getCurrentNode();
             AVMNode retVal = dir.lookupChild(lookup, name, -1, false, includeDeleted);
             lPath.setFinalStore(lookup.getFinalStore());
             return retVal;
         }
-        catch (AVMException re)
+        else
         {
-            if (re instanceof AVMCycleException)
-            {
-                throw re;
-            }
             return null;
         }
     }
@@ -535,9 +519,9 @@ class LayeredDirectoryNodeImpl extends DirectoryNodeImpl implements LayeredDirec
         {
             return null;
         }
-        try
+        Lookup lookup = AVMRepository.GetInstance().lookupDirectory(-1, mine.getIndirection());
+        if (lookup != null)
         {
-            Lookup lookup = AVMRepository.GetInstance().lookupDirectory(-1, mine.getIndirection());
             DirectoryNode dir = (DirectoryNode)lookup.getCurrentNode();
             AVMNode child = dir.lookupChild(lookup, name, -1, false, includeDeleted);
             if (child == null)
@@ -546,12 +530,8 @@ class LayeredDirectoryNodeImpl extends DirectoryNodeImpl implements LayeredDirec
             }
             return child.getDescriptor(lookup);
         }
-        catch (AVMException e)
+        else
         {
-            if (e instanceof AVMCycleException)
-            {
-                throw e;
-            }
             return null;
         }
     }
diff --git a/source/java/org/alfresco/repo/avm/LayeredFileNodeImpl.java b/source/java/org/alfresco/repo/avm/LayeredFileNodeImpl.java
index adcd459af0..3385740d3c 100644
--- a/source/java/org/alfresco/repo/avm/LayeredFileNodeImpl.java
+++ b/source/java/org/alfresco/repo/avm/LayeredFileNodeImpl.java
@@ -79,6 +79,10 @@ class LayeredFileNodeImpl extends FileNodeImpl implements LayeredFileNode
     {
         // LayeredFileNodes are always copied.
         Lookup lookup = AVMRepository.GetInstance().lookup(-1, fIndirection, false);
+        if (lookup == null)
+        {
+            throw new AVMException("Unbacked layered file node.");
+        }
         AVMNode indirect = lookup.getCurrentNode();
         if (indirect.getType() != AVMNodeType.LAYERED_FILE &&
             indirect.getType() != AVMNodeType.PLAIN_FILE)
@@ -250,6 +254,10 @@ class LayeredFileNodeImpl extends FileNodeImpl implements LayeredFileNode
     public ContentData getContentData(Lookup lPath)
     {
         Lookup lookup = lPath.getAVMStore().getAVMRepository().lookup(-1, getIndirection(), false);
+        if (lookup == null)
+        {
+            throw new AVMException("Invalid target.");
+        }
         AVMNode node = lookup.getCurrentNode();
         if (!(node instanceof FileNode))
         {
diff --git a/source/java/org/alfresco/repo/avm/VersionRootDAO.java b/source/java/org/alfresco/repo/avm/VersionRootDAO.java
index c9cba6e2fd..af8cf55c39 100644
--- a/source/java/org/alfresco/repo/avm/VersionRootDAO.java
+++ b/source/java/org/alfresco/repo/avm/VersionRootDAO.java
@@ -68,4 +68,11 @@ public interface VersionRootDAO
      * @return The highest numbered version.
      */
     public VersionRoot getMaxVersion(AVMStore store);
+    
+    /**
+     * Get the highest numbered id from all the versions in a store.
+     * @param store The store.
+     * @return The highest numbered id.
+     */
+    public Integer getMaxVersionID(AVMStore store);
 }
diff --git a/source/java/org/alfresco/repo/avm/hibernate/VersionRootDAOHibernate.java b/source/java/org/alfresco/repo/avm/hibernate/VersionRootDAOHibernate.java
index ce2519461a..d7a22ff2e7 100644
--- a/source/java/org/alfresco/repo/avm/hibernate/VersionRootDAOHibernate.java
+++ b/source/java/org/alfresco/repo/avm/hibernate/VersionRootDAOHibernate.java
@@ -141,4 +141,17 @@ class VersionRootDAOHibernate extends HibernateDaoSupport implements
                                                "(select max(v.versionID) from VersionRootImpl v)");
         return (VersionRoot)query.uniqueResult();
     }
+    
+    /**
+     * Get the highest numbered id from all the versions in a store.
+     * @param store The store.
+     * @return The highest numbered id.
+     */
+    public Integer getMaxVersionID(AVMStore store)
+    {
+        Query query = getSession().createQuery("select max(vr.versionID) from VersionRootImpl vr " + 
+                                               "where vr.avmStore = :store");
+        query.setEntity("store", store);
+        return (Integer)query.uniqueResult();
+    }
 }
diff --git a/source/java/org/alfresco/service/cmr/avm/AVMService.java b/source/java/org/alfresco/service/cmr/avm/AVMService.java
index dac0db83a1..83b434a625 100644
--- a/source/java/org/alfresco/service/cmr/avm/AVMService.java
+++ b/source/java/org/alfresco/service/cmr/avm/AVMService.java
@@ -192,15 +192,6 @@ public interface AVMService
      */
     public void createDirectory(String path, String name);
     
-    /**
-     * Create a new directory, in an already copy on written node.
-     * This should only be used if you really know what you're doing.
-     * @param parent The parent node.
-     * @param name The name of the new directory.
-     * @return A descriptor for the newly created directory.
-     */
-    public AVMNodeDescriptor createDirectory(AVMNodeDescriptor parent, String name);
-    
     /**
      * Create a new layered file.
      * @param targetPath The simple absolute path that the new file will point at.
@@ -695,28 +686,6 @@ public interface AVMService
      */
     public void link(String parentPath, String name, AVMNodeDescriptor toLink);
     
-    /**
-     * This is a more dangerous version of link, which assumes
-     * that copy on write has occurred for the parent node. This is
-     * an internal call. Don't use it if you don't know precisely
-     * what you are doing.
-     * @param parent The parent node.
-     * @param name The name to give the child.
-     * @param child The child node to link.
-     */
-    public void link(AVMNodeDescriptor parent, String name, AVMNodeDescriptor child);
-    
-    /**
-     * Flatten a direct child of a layered directory. This does
-     * the equivalent of removing the given child from the directory 
-     * and then doing an uncover. This routine makes many dangerous 
-     * assumptions and is only for use by AVMSyncService. Don't use it
-     * if you don't know precisely what you are doing.
-     * @param lDir The layered directory node.
-     * @param name The name to flatten.
-     */
-    public void flatten(AVMNodeDescriptor lDir, String name);
-    
     /**
      * Force copy on write of a path.
      * @param path The path to force.