iCal hung on a sync with Google calendars and kept hanging everytime I restarted it, even after restarting the whole machine.

I found some advice on this in a few posts.

One “Fix an iCal ‘application not responding’ occasional hang” was more about occasional long pauses and suggested selecting”Reset Sync History” in  “iSync » Preferences”.  Another  “Fix an iCal hang due to system date reset” suggested resetting the ‘lastHearBeatDate‘ in Library/Preferences/com.apple.iCal.plist. Neither worked, but prompted by the latter I used TimeMachine (yawn yawn how do they make it sooooo sloooow), to restore copies of all the iCal plist files in Library/Preferences/, but again to no avail.

So several good suggestions, but none worked.

Happily I saw a comment lower down on “Fix an iCal hang due to system date reset” which suggested moving the complete ~/Library/Calendars folder out to the desktop and then recopying the calendar files in one by one after restarting iCal. I didn’t do this as such, but instead in ~/Library/Calendars there are a number of ‘Calendar Cache‘ files and also a folder labelled Calendar Sync Changes. I removed these, restarted and … it works 🙂

Hardly easy for the end user though :-/