Imagine the following scenario: You perform a full backup of mailbox store on Exchange 2003. You move a mailboxe from the backed-up store to an Exchange 2007 server. You try to leverage the Recovery Storage Group feature on the Exchange 2003 server to restore the contents of the mailbox in question using ExMerge to restore/export the contents of the mailbox from a date before the mailbox was moved. The ExMerge export phase fails with the following error in the exmerge.log: Error opening message store...