I have noticed something strange that I wondered if anyone had noticed - I can't see anything about it on the Internet, so wanted to check if it was relevant to my environment.
I had a mailbox that was originally on Exchange 2003 SP2. It was then migrated to Exchange 2007 and after a few days I gave myself Full Mailbox access to the mailbox.
After a few days, I then moved it back to Exchange 2003. I tried to access the mailbox via my Outlook profile (I had it listed and could access it when it was on 2007). However couldn't. I waited for a few years - no joy. Eventually I checked the permissions of the mailbox in ADUC, and found that I no longer had rights on it.
If permissions are given to a mailbox when it is on 2007, are these permissions lost if it is moved back to 2003 again?