My iPhone 4S with the latest iOS 6.1.1 will NOT sync the contents of its calendar with Outlook 2010 or vice versa, in spite of all suggestions I've tried from this forum! It used to sync both ways with no problems, before the latest rounds of "updates" on iTunes (11.0.1) and iPhone software. What gives? I've tried everything and am pulling my hair out.
iPhone 4S, iOS 6.1.1, iTunes 11.0.1; Outlook 2010
Well you didn't say what you've tried, but if you haven't already, try resetting your sync history in iTunes (Edit>Preferences>Devices).
Thanks Randers4. You are right - I neglected to tell all the stuff I've tried. I did as you suggested about resetting the sync history - I even closed and reopened everything, and tried syncing with Outlook open, and then closed. The only change is it did download (sync) one new calendar event I added to my Outlook calendar and it put it on my iphone calendar, but it did NOT put my new iphone calendar items on my Outlook calendar. Not sure what else to try!
There are some additional troubleshooting steps you can take a look at here:
http://support.apple.com/kb/HT1692
My iPhone 4S will NOT sync calendars either way with Outlook 2010
