I have Outlook 2011 set to sync with my iCal and Address Book. On my computer everything is playing together nicely. Not so with my iPhone. Everything was working fine until I added a couple of new contacts into Outlook. The contacts synced fine with Address Book. But the next time I synced my iphone I got a warning message. It asked if I wanted to add the new contacts but warned it would "modify" 793 contacts - meaning it would "modify" all of my existing contacts. I approved that. The sync seemed to work and all the contacts all look fine. HOWEVER - all the events were removed from my calendar on my iPhone. AND the birthdays all show up - which I did not have it set to show birthdays before. So this indicates to me that something with the contact sync added the birthday info from the contacts as part of its "modifying" them and wiped out everything else on the calendars in my iPhone. I have added a couple of new events, synced, and those show up. Just nothing from before I synced the contacts. The thing is - everything still shows up fine on both iCal and the Outlook Calendar. Help! If it were any other app I could just remove it and reinstall it and the problem would probably fix itself. But I can see no way to do that with the iPhone calendar.