Reading Time: < 1 minute Recently a colleague of mine migrated the mailboxes from Exchange 2003 to Exchange 2010. But he noticed something weird, in the Exchange Management Console (2010) the newly migrated users could be seen, but in the Exchange System Manager (2003) he could still see active mailboxes. He confirmed that they were still using the Exchange 2003 server. About 50% were migrated and the other half was still on Exchange 2003 and could therefor not be move via Console. We tried several