After iCloud sync, iCal is stuck "Upgrading iCal Calendars..."

This response worked for me:

Ferd II Oak Harbor, Washington

birddogdesign,

Quit iCal, go to your Macintosh HD/Users/yourusername/Library/Calendars folder, and delete all files with the name "Calendar Cache."

Then log out/in or restart and see what happens when you restart iCal.

This solution didn't work for me. I found the "Calendars" folder but there were no files named "Calendar cache". Any other solutions?

I had the same problem. I upgraded my system (which didn't seem to do anything). Then, I went to settings: ICloud and unchecked ICal, then, I rechecked it. It took a minute for everything to come back, but it all looks good. And no more Upgrading message.

That worked for me!! Thanks!

On Lion it is hard to access the Library folder. I used Spotlight to find "calendar cache", clicked on it in the Spotlight list, and saw a textedit version. I command-clicked on the file name and then clicked on the folder in the drop down list. Then I deleted the file "calendar cache" from that folder.

When I restarted my MacBook, iCal started up with the same "Upgrading" message. Oh, great! But after a few minutes that message went away.

Even after all this fuss and bother, I still have duplicates. I don't think I'll run Calendar Cleaner again to remove them. Who knows what evil lurks in the hearts of Apple operating systems:) "The computer for the rest of us"??

Sunny0000's idea worked for me. Don't know how it started. I thought it was thr latest Lion OS update but wasted a few hours doing a reinstall of the OS, backing up calenders and deleting plists. None of that did anything.

This was successful, although I had to use spotlight to find the Calendar cache file. Deleting it was apparently the "fix".

Many thanks!