Calendar is incessantly posting error messages that it cannot change or delete an event on my Exchange calendar. I have tried the "revert to server, try again, and ignore" more times than I can count. I even deleted the exchange from my connection and reinstalled without help. Even when I have deleted the Exchange, it continues to have this error window every 60 seconds. I am ready to stop using the computer just for the stress of it. Any suggestions or help before this screen winds up with a shoe in it?