This is an exact description of the problem, and I've included some of the steps I have performed to troubleshoot.
1. When I'm viewing the calendar, I am unable to add new appts.
2. If I change the time of and old recurring appointment (from All day event to a timed event (like 9:00 am to 10:00 am)), the appointment will revert back to its original state after about 1 minute. It reverts back right before your eyes!
3. Reminders keep coming up. If I dismiss them all, they all come back. If I dismiss them one by one, they call come back. Every time.
What I have tried:
1. Detect and repair
2. Uninstall and reinstall
3. work offline
4. confirm that viruscan is NOT scanning exchnage
I am stumped on this one. Oh, this is only happening with one user.