Exchange 2010 Troubleshooting:Mailbox move error (tombstone is present)
In your Exchange environment, mailbox moves are a normal routine for an administrator, however on the odd occasion you do have 1 or 2 that fail, below is a failure of a mailbox move:
"Error: Mailbox XXXXX tombstone is present in the target database. It must be cleaned up before the move operation can proceed."
https://www.collaborationpro.com/wp-content/uploads/2018/12/mailbox-move.png
To fix this error, you would need to export the mail to a .PST file and re-create the mailbox and then import the .PST file again.
Rebooting the server or DAG does not make any difference.