Exchange 2010 permissions issue
Right having a tricky issue with permissions on Exchange 2010. One of the users has access to a few other user's mailboxes. He has them added in Outlook and every few weeks will get errors saying he does not have access to them. The only way to solve it is to take off his access to the mailboxed then re-add them. This then works for a few weeks and then it all goes wrong again.
We have tried fully updating the server, installing Exchange 2010 SP1, and even the step of recreating the user's entire AD account and mailbox. The server is running server 2008 R2, along with two domain controllers also running 2008 R2.
Short of flattening it anyone got an idea?