Troubleshooting: Azure AD Connect Stops Syncing After Update

Symptoms

Synchronization tasks within Azure AD are not kicking off at all. No errors are present in the application/system logs. In fact, nothing is in the application logs.

Resolution

Make sure all the appropriate ADSynchScheduler properties are set correctly.

1. Open Microsoft Azure Active Directory Module for Windows PowerShell.
    
2. Run the following command:
   

   Get-ADSyncScheduler

3. The result should be something like this:

   AllowedSyncCycleInterval            : 00:30:00
   CurrentlyEffectiveSyncCycleInterval : 00:30:00
   CustomizedSyncCycleInterval         : 
   NextSyncCyclePolicyType             : Delta
   NextSyncCycleStartTimeInUTC         : 12/15/2017 5:19:45 PM
   PurgeRunHistoryInterval             : 7.00:00:00
   SyncCycleEnabled                    : True
   MaintenanceEnabled                  : True
   StagingModeEnabled                  : False
   SchedulerSuspended                  : False
   SyncCycleInProgress                 : False
   

4. Make sure SyncCycleEnabled is set to True and SchedulerSuspended is set to False. If they aren't, run one of the following commands to switch them:

   Set-ADSyncScheduler -SyncCycleEnabled $True
   Set-ADSyncScheduler -SchedulerSuspended $False

5. In the incident that cause this article to be written, the server was rebooted. That may not be necessary.

Cause

Based on the incident that caused this article to be written and some reading online, it is somewhat common for one of these properties to be left in an undesired state after an upgrade of the Azure AD Connect application. This is similar to what has been seen in the past from Microsoft updates of other products that left them in “maintenance mode” after the task finished.