Restore Mailboxes from Exchange 2007

Have you run ESUTIL on the database to compress? I recently migrated a client from 2007 to 2010. And the method I've always used is to go to the 2010 box and initiate a "New local Move..." on the individual mailbox. What I'm saying e is that you are doing a "Move" not a "copy". You have to, because you don't want the user's mail to be in two locations at the same time. So if you move the mail from one database to another, and you move all mailboxes then the 2007 database is emptied out. It is essentially Gigabytes of empty space. I think that is why you keep coming up with 0 when you do a "Get-Mailbox". If you make a copy of the database and run ESUTIL on it to compress I think you'll find it compresses way down to almost nothing. You may have a huge, empty, file on your hands.