There are several suggestions for fixing this online:
- Verify that AD permissions are inheriting to the user account.
- Restart the Exchange Mailbox Replication Service
When I looked at the application log on the Exchange 2007 server, I noticed that there was an error about the Mailbox Submission Service not responding for 30 minutes. This added to my suspicions about the Exchange 2007 actually causing the original completing error.
After restarting the Exchange services on the Exchange 2007 server all was good. To allow the Information Store service to restart, I needed to suspend all of the queued moves. Until I did that, it hung at stopping.
After restarting, a couple of the moves that were completing failed and other completed. Not a problem, as moving those failed mailboxes again was easy enough.