I have Exchange 2007. I started migrating to Exchange Online before I realized that the migration process discards mailbox data during the migration . As completing the migration for one mailbox, I deleted the local source mailbox using the Microsoft Online Services Migration Tool. I would like to recover the original mailbox and revert to it rather than the migrated version. However, when I try to follow the instructions on How to Recover a Deleted Mailbox , the Connect Mailbox wizard never appears and there are no mailboxes listed for recovery. When I use the Exchange Management Shell to list disconnected mailboxes, nothing is returned. I double-checked the mailbox store, and it indicates that deleted mailboxes should be retained for the default period (30 days). So why can't I find the deleted/disconnected mailbox? Did the migration tool perform a more complete deletion? Is it possible for me to recover the original database?

Upon further investigation, it appears the deleted mailbox is still present on the server, but the DisconnectDate is null, so it doesn't appear in the disconnected mailboxes, and as such I'm unable to reconnect it to any user account. I'm working with the Exchange Online technical support to try to find a way to reconnect the mailbox to a user account.

Have you tried running clean-mailboxdatabase against the store it was in? http://technet.microsoft.com/en-us/library/bb124076(EXCHG.80).aspx

Excellent. After running Clean-MaxlboxDatabase -Identity 'Mailbox Database' The disconnected mailbox now appears in the disconnected mailboxes. I understand I can probably now reconnect this mailbox to a user account. Thanks AndyD_!