Originally Posted by solret
Here's an answer that worked from BSteck on the Google support forum.
On my HTC Phone (running Android 2.2), I went to Settings > Applications > Manage Applications > Running > Calendar Storage. I then pushed "Clear Data" and then "Force Stop" (because I wanted it to reload).
The phone paused for a brief moment when returning to Home and then the calendar was syncing to my gmail calendars. I figure that as long as all your information is backed up at gcal, you should be fine. Good luck!
Worked for me too, Thanks!
Just so people don't freak out... it took some time for my Calendars to reappear on my phone, but after 2 min, all was good