I am the exchange administrator, and my COO just received a new MacBook Air - we have Outlook 2011 set up, but he is receiving a sync error on about 15 calendar entries.  I've tried deleting entries that are old and no longer apply, completely from his calendar but the errors still appear.  Need help troubleshooting and narrowing down where these things are coming from so I can get rid of that exclamation point in the bottom right corner of the window.