diff --git a/source/java/org/alfresco/repo/imap/AlfrescoImapFolder.java b/source/java/org/alfresco/repo/imap/AlfrescoImapFolder.java
index 50b3fdcf5e..6b0d65e52c 100644
--- a/source/java/org/alfresco/repo/imap/AlfrescoImapFolder.java
+++ b/source/java/org/alfresco/repo/imap/AlfrescoImapFolder.java
@@ -317,7 +317,11 @@ public class AlfrescoImapFolder extends AbstractImapFolder implements Serializab
         NodeRef sourceNodeRef = extractNodeRef(message);
         if (isMoveOperation(sourceNodeRef))
         {
-            uid = moveNode(this.folderInfo, message, flags, sourceNodeRef);
+            uid = copyOrmoveNode(this.folderInfo, message, flags, sourceNodeRef, true);
+        }
+        else if (sourceNodeRef != null)
+        {
+            uid = copyOrmoveNode(this.folderInfo, message, flags, sourceNodeRef, false);
         }
         else
         {
@@ -341,13 +345,21 @@ public class AlfrescoImapFolder extends AbstractImapFolder implements Serializab
      * @throws FileNotFoundException
      */
     @SuppressWarnings("deprecation")
-    private long moveNode(FileInfo folderInfo, MimeMessage message, Flags flags, NodeRef sourceNodeRef)
+    private long copyOrmoveNode(FileInfo folderInfo, MimeMessage message, Flags flags, NodeRef sourceNodeRef, boolean move)
             throws FileExistsException, FileNotFoundException
     {
         FileFolderService fileFolderService = serviceRegistry.getFileFolderService();
         FileFilterMode.setClient(FileFilterMode.Client.imap);
         fileFolderService.setHidden(sourceNodeRef, false);
-        FileInfo messageFile = fileFolderService.move(sourceNodeRef, folderInfo.getNodeRef(), null);
+        FileInfo messageFile = null;
+        if (move)
+        {
+            messageFile = fileFolderService.move(sourceNodeRef, folderInfo.getNodeRef(), null);
+        }
+        else
+        {
+            messageFile = fileFolderService.copy(sourceNodeRef, folderInfo.getNodeRef(), null);
+        }
         final long newMessageUid = (Long) messageFile.getProperties().get(ContentModel.PROP_NODE_DBID);
         imapService.setFlag(messageFile, Flag.RECENT, true);
         imapService.setFlag(messageFile, Flag.DELETED, false);
@@ -367,6 +379,7 @@ public class AlfrescoImapFolder extends AbstractImapFolder implements Serializab
         String uuid = null;
         String messageId = null;
         NodeRef result = null;
+        NodeService nodeService = serviceRegistry.getNodeService();
         try
         {
             messageId = message.getMessageID();
@@ -391,6 +404,28 @@ public class AlfrescoImapFolder extends AbstractImapFolder implements Serializab
                 uuid = messageId;
             }
             result = new NodeRef(StoreRef.PROTOCOL_WORKSPACE, "SpacesStore", uuid);
+            if (nodeService.exists(result) == false)
+            {
+                result = null;
+            }
+        }
+        
+        if(result == null)
+        {
+            //check X-Alfresco-NodeRef-ID header
+            try
+            {
+                uuid = message.getHeader(AlfrescoImapConst.X_ALF_NODEREF_ID)[0];
+                result = new NodeRef(StoreRef.PROTOCOL_WORKSPACE, "SpacesStore", uuid);
+                if (nodeService.exists(result) == false)
+                {
+                    result = null;
+                }
+            }
+            catch (MessagingException e)
+            {
+                //Do nothing
+            }
         }
         return result;
     }
diff --git a/source/test-java/org/alfresco/repo/imap/ImapServiceImplTest.java b/source/test-java/org/alfresco/repo/imap/ImapServiceImplTest.java
index b4a3387b37..ad0caea97b 100644
--- a/source/test-java/org/alfresco/repo/imap/ImapServiceImplTest.java
+++ b/source/test-java/org/alfresco/repo/imap/ImapServiceImplTest.java
@@ -921,6 +921,56 @@ public class ImapServiceImplTest extends TestCase
         assertEquals("There should be only one node in the destination folder", 1, nodeService.getChildAssocs(destinationNode.getNodeRef()).size());
     }
     
+    /**
+     * Test for MNT-12420
+     * 
+     * @throws Exception 
+     */
+    public void testMoveViaAppendAndDelete() throws Exception
+    {
+        AlfrescoImapUser poweredUser = new AlfrescoImapUser((USER_NAME + "@alfresco.com"), USER_NAME, USER_PASSWORD);
+        String fileName = "testfile" + GUID.generate();
+        String destinationName = "testFolder" + GUID.generate();
+        String destinationPath = IMAP_ROOT + AlfrescoImapConst.HIERARCHY_DELIMITER + destinationName;
+        String nodeContent = "test content";
+        NodeRef root = findCompanyHomeNodeRef();
+        AuthenticationUtil.setRunAsUserSystem();
+
+        // Create node and destination folder
+        FileInfo origFile = fileFolderService.create(root, fileName, ContentModel.TYPE_CONTENT);
+        ContentWriter contentWriter = contentService.getWriter(origFile.getNodeRef(), ContentModel.PROP_CONTENT, true);
+        contentWriter.setMimetype("text/plain");
+        contentWriter.setEncoding("UTF-8");
+        contentWriter.putContent(nodeContent);
+
+        FileInfo destinationNode = fileFolderService.create(root, destinationName, ContentModel.TYPE_FOLDER);
+        nodeService.addAspect(origFile.getNodeRef(), ImapModel.ASPECT_IMAP_CONTENT, null);
+        nodeService.addAspect(origFile.getNodeRef(), ContentModel.ASPECT_TAGGABLE, null);
+
+        // Save the message and set X-Alfresco-NodeRef-ID header
+        SimpleStoredMessage origMessage = imapService.getMessage(origFile);
+        origMessage.getMimeMessage().addHeader(AlfrescoImapConst.X_ALF_NODEREF_ID, origFile.getNodeRef().getId());
+        origMessage.getMimeMessage().saveChanges();
+
+        // Append the message to destination
+        AlfrescoImapFolder destinationMailbox = imapService.getOrCreateMailbox(poweredUser, destinationPath, true, false);
+        long uuid = destinationMailbox.appendMessage(origMessage.getMimeMessage(), flags, null);
+        
+        // Delete the node
+        imapService.setFlag(origFile, Flags.Flag.DELETED, true);
+        imapService.expungeMessage(origFile);
+
+        // Check the destination has copy of original file and only this file
+        FileInfo copiedNode = fileFolderService.getFileInfo(nodeService.getNodeRef(uuid));
+        assertNotNull("The file should exist.", copiedNode);
+        assertEquals("The file name should not change.", fileName, copiedNode.getName());
+        NodeRef copiedParentNodeRef = nodeService.getPrimaryParent(copiedNode.getNodeRef()).getParentRef();
+        assertEquals("The parent should change to destination.", destinationNode.getNodeRef(), copiedParentNodeRef);
+        assertEquals("There should be only one node in the destination folder", 1, nodeService.getChildAssocs(destinationNode.getNodeRef()).size());
+        assertTrue("New node should have original node aspects", nodeService.hasAspect(copiedNode.getNodeRef(), ContentModel.ASPECT_TAGGABLE));
+    }
+    
+    
     /**
      * @param mailbox - {@link AlfrescoImapFolder} instance which should be checked
      */