My exchange DB was having issues and I tried to migrate this mailbox and it failed in the past.
I ran and offline defrag and it worked perfect, exchange is no longer having issues. However there are 10 Disconnected Mailboxes I can do nothing with. I try to "connect" to the original existing Active Directory account and it doesn't pick them up. If you got to "MAILBOX" in Management Console, you still see the names. I tried to re-migrate the account to an Archive DB and I got this failure below.
Summary: 1 item(s). 0 succeeded, 1 failed.
Elapsed time: 00:00:13
Error was found for Kamron X (Kamron@X.com) because: Error occurred in the step: Preparing mailbox to be moved. Failed to copy basic mailbox information with error: A duplicate mailbox was found due to problems during a Move Mailbox procedure. The duplicate mailbox has been deleted. Try again later., error code: -1056749241
Exchange Management Shell command attempted:
'X.com/Former Employees/Kamron X' | move-mailbox -TargetDatabase 'MAIL\First Storage Group\Archive'
Elapsed Time: 00:00:13
Now the zinger, some of the mailboxes SUCCESSFULLY migrated from old DB to a new DB and they appear as disconnected. The Active Directory Object is "Disabled" as they are no longer employees, however I need to keep their email box.