diff --git a/src/main/java/org/alfresco/repo/attributes/PropTablesCleaner.java b/src/main/java/org/alfresco/repo/attributes/PropTablesCleaner.java
index 99c000993b..3287586a8c 100644
--- a/src/main/java/org/alfresco/repo/attributes/PropTablesCleaner.java
+++ b/src/main/java/org/alfresco/repo/attributes/PropTablesCleaner.java
@@ -1,33 +1,34 @@
-/*
- * #%L
- * Alfresco Repository
- * %%
- * Copyright (C) 2005 - 2016 Alfresco Software Limited
- * %%
- * This file is part of the Alfresco software. 
- * If the software was purchased under a paid Alfresco license, the terms of 
- * the paid license agreement will prevail.  Otherwise, the software is 
- * provided under the following open source license terms:
- * 
- * Alfresco is free software: you can redistribute it and/or modify
- * it under the terms of the GNU Lesser General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- * 
- * Alfresco is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU Lesser General Public License for more details.
- * 
- * You should have received a copy of the GNU Lesser General Public License
- * along with Alfresco. If not, see <http://www.gnu.org/licenses/>.
- * #L%
- */
+/*
+ * #%L
+ * Alfresco Repository
+ * %%
+ * Copyright (C) 2005 - 2016 Alfresco Software Limited
+ * %%
+ * This file is part of the Alfresco software. 
+ * If the software was purchased under a paid Alfresco license, the terms of 
+ * the paid license agreement will prevail.  Otherwise, the software is 
+ * provided under the following open source license terms:
+ * 
+ * Alfresco is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ * 
+ * Alfresco is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ * 
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with Alfresco. If not, see <http://www.gnu.org/licenses/>.
+ * #L%
+ */
 package org.alfresco.repo.attributes;
 
 import org.alfresco.repo.domain.propval.PropertyValueDAO;
 import org.alfresco.repo.lock.JobLockService;
 import org.alfresco.repo.lock.LockAcquisitionException;
+import org.alfresco.repo.security.sync.ChainingUserRegistrySynchronizer;
 import org.alfresco.service.namespace.NamespaceService;
 import org.alfresco.service.namespace.QName;
 import org.alfresco.util.PropertyCheck;
@@ -74,11 +75,14 @@ public class PropTablesCleaner
     {
         checkProperties();
         
-        String lockToken = null;
+        String propCleanUplockToken = null;
+        String ldapSyncLockTocken = null;
         try
         {
-            // Get a lock
-            lockToken = jobLockService.getLock(LOCK_QNAME, LOCK_TTL);
+            // Get a lock for cleanup
+            propCleanUplockToken = jobLockService.getLock(LOCK_QNAME, LOCK_TTL);
+            // Get a lock for LDAP sync as well, see REPO-4556
+            ldapSyncLockTocken = jobLockService.getLock(ChainingUserRegistrySynchronizer.LOCK_QNAME, LOCK_TTL);
             propertyValueDAO.cleanupUnusedValues();
         }
         catch (LockAcquisitionException e)
@@ -90,11 +94,22 @@ public class PropTablesCleaner
         }
         finally
         {
-            if (lockToken != null)
+            if (propCleanUplockToken != null)
             {
                 try
                 {
-                    jobLockService.releaseLock(lockToken, LOCK_QNAME);
+                    jobLockService.releaseLock(propCleanUplockToken, LOCK_QNAME);
+                }
+                catch (LockAcquisitionException e)
+                {
+                    // Ignore
+                }
+            }
+            if (ldapSyncLockTocken != null)
+            {
+                try
+                {
+                    jobLockService.releaseLock(ldapSyncLockTocken, ChainingUserRegistrySynchronizer.LOCK_QNAME);
                 }
                 catch (LockAcquisitionException e)
                 {
diff --git a/src/main/java/org/alfresco/repo/security/sync/ChainingUserRegistrySynchronizer.java b/src/main/java/org/alfresco/repo/security/sync/ChainingUserRegistrySynchronizer.java
index 6244177fee..388404d15f 100644
--- a/src/main/java/org/alfresco/repo/security/sync/ChainingUserRegistrySynchronizer.java
+++ b/src/main/java/org/alfresco/repo/security/sync/ChainingUserRegistrySynchronizer.java
@@ -113,7 +113,7 @@ public class ChainingUserRegistrySynchronizer extends AbstractLifecycleBean
     private static final Log logger = LogFactory.getLog(ChainingUserRegistrySynchronizer.class);
 
     /** The name of the lock used to ensure that a synchronize does not run on more than one node at the same time. */
-    private static final QName LOCK_QNAME = QName.createQName(NamespaceService.SYSTEM_MODEL_1_0_URI,
+    public static final QName LOCK_QNAME = QName.createQName(NamespaceService.SYSTEM_MODEL_1_0_URI,
             "ChainingUserRegistrySynchronizer");
 
     /** The time this lock will persist for in the database (now only 2 minutes but refreshed at regular intervals). */