I am the exchange administrator trying to open other users mailbox in outlook 2003. I have added myself as an Exchange Full Administrator. Added myself to the server itself as an administrator, the information store, and database. I am also a member of the domain and enterprise admins. I can see on the users AD properties that I have full access, but when i try to open their mailbox I get "cannot expand folder". If i go to the mailbox and right click the mailbox and go to properties I get "the set of folders cannot be opened". I am also not able to open the folder using open other users folder. This is happening for most of the users but a couple of mailboxes will allow me to open them.