I've recently encountered a problem where I need to recover some previously deleted exchange mailboxes from backups in Exchange 2007.
What I've done so far is gone to our backup, recovered the mailbox database file, mounted it into a Recovery Storage Group, and then tried to run the command:
restore-mailbox -identity 'FirstName LastName' -rsgdatabase "Server\RSG\Mailbox Database"
When I run the command I get an error that the mailbox could not be found in the Recovery Storage Group:
Restore-Mailbox : The specified mailbox "6439a8d7-f75d-4a4e-a0b0-f7278235c4d3" does not exist on database "Server\RSG\Mailbox Database".
The recovered mailbox database that I'm using is from 2 months before I actually deleted the mailboxes I'm trying to recover. It's possible that the accounts could have been disabled at this point though.