User does not have access to an archive

Users require write access to an archive in order to archive, and read access in order to retrieve. This applies even for background archiving. A user must also be the owner of the mailbox or be a member of the local Administrators group on the system that is running the Exchange Mailbox task.

On Exchange 2000, a user can also have access to an archive by using an account that has been granted full access in the mailbox rights attribute. You can set the attribute using the Active Directory Users and Computers snap-in.