Tuesday, June 6, 2017


Today while moving a mailbox from on-premises to Office 365 in a hybrid environment, I got the following error:
Transient error SourceMailboxAlreadyBeingMovedTransientException has occurred. The system will retry (5/620).
This error occurs when a previous move attempt did not get cleaned up properly. From a bit of reading, this should timeout and fix itself after about 2 hours. However, since I didn't want to wait that long, I did the following that got it going again.
  • IISReset.exe to restart the web services
  • Restart the Microsoft Exchange Mailbox Replication service
It is possible that only one of those two items was required, but I was more concerned about getting the move going than recording exact details.

1 comment:

  1. We worked around this same issue via registry key by adding KeepAliveTime REG_DWORD and use 5 minutes instead of 2 hours.