After the correct updates have finally been released last week (Exchange 2010 SP3 and Exchange 2013 CU1) it was time to get some Guinea Pigs… sorry, “Test Users” migrated over to Exchange 2013. Some of the very small mailboxes were fine, but when it came to a real users mailbox the progressed appeared awfully slow. After taking a look at the log, I found it was full of:

The job is currently stalled due to ‘Content Indexing’ lagging behind on resource ‘CiAgeOfLastNotification()’

The message is a little misleading as it appeared that the content indexing wasn’t lagging at all, it was plain not working and showing as failed for the mailbox database. After many reboots and diagnostics I still couldn’t figure this out, so I turned to google and finally after digging quite a bit I found the answer. Please be aware that you will find this issue is most commonly talked about in reference to DAG groups replicating, but its a similar issue with migrations. The answer was thanks to Bright Murewanhema on the technet forums (link), who contacted Microsoft Support for the resolution. It appears that there’s a bug in Exchange 2013 RTM (which isn’t fixed by CU1 it appears) which causes the Exchange 2013 to not setup all the groups needed in Active Directory. The one in particular is called “ContentSubmitters”. You need to:

  1. Create the group yourself manually in Active Directory (I created in the existing exchange groups OU)
  2. Change the security on the group (not the members!) to allow “Administrators” and “NetworkService” accounts “Full Control”.
  3. Restart “Microsoft Exchange Search” on your mailbox server(s)
  4. Restart “Microsoft Exchange Search Host Controller” on your mailbox server(s)

After you have completed the above you should notice the mailbox databases content index status change to “Healthy” instead of “Failed”, and your migrations will start to transfer at a much more bearable rate.