We are migrating from Exchange 2000 to 2007 and have already successfully moved several mailboxes via the Move Mailbox wizard from the Exchange console. However, when we tried to move a user with a 1gb mailbox it hung with a continuing status of: “Opening source mailbox”. After 20 hours we killed the process. Unfortunately at that point the mailbox was left in limbo and we couldn't access/open it. We tried rebooting the 2007 box, no luck but, after rebooting the 2000 box everything was fine once again. Has anybody else had this problem or is anyone aware of a solution?