I'm upgrading to exchange 2010 from 2003 and have run into a problem with scheduling resources. I created a test resource on my old server, added a few appointments, then migrated it to the new 2010 environment. When I attempt to reserve it again using an account still on the 2003 server it fails to work...no errors at all but nothing gets entered in the resource calendar. Same in the other direction...users on 2010 can't make reservations on 2003 resources. Is this normal behavior? If so is there a work around? Otherwise I'd have to do a full conversion on most mailboxes at the same time to prevent scheduling issues.