Problem:
I have been syncing my iPhone using USB that connects to my computer (PC with Windows 7 OS) and I did not have any issue synchronizing my Calendar, Contacts etc. until recently when I tried to sync my iPhone with my computer (using iTunes of course), I suddenly received the following error message:
Solution: Solving this issue quite easy. Just follow the step by step below.
1. Connect your iPhone to your computer and open iTunes (If iTunes does not launch automatically, double click the application to launch iTunes).
2. Once iTunes is running, click on the iPhone in the left navigation pane
3. Once the iPhone is highlighted click the Info tab and scroll to the bottom to see the Advanced settings as shown below
4. Under “Replace Information On The iPhone”, check box next to Calendars (this will cause the iPhone calendar to be completely overwritten with the calendar items from the calendar you are syncing with)
5. Click “Apply” to start the synchronization.
I hope this helps!