Google Calendar sync not working in Mountain Lion

Solution 1:

I started encountering a similar problem with my Google for Business account last week. Mail.app was okay but Calendar refused to sync, returning the error message that "Your calendar URL is not a location that supports this request." every time Calendar tried to sync.

The solution was delete the account completely from System Preferences -> Mail, Contacts & Calendars. Generate a new one-time password for the account (I use two-factor authentication on all my Google accounts). And the re-add the account in that System Preferences pane.

All is well now after doing this.

Solution 2:

Note this problem occurred for me after changing my Google password.

On starting Calendar (a week or two after changing my password) it asked me for my password, as it couldn't access my Google account [expected behaviour]. I gave it my new password, and it seemed happy. HOWEVER the problem still remained.

The fix is definitely like the other poster mentioned, although you don't need to re-add the account, you only need to change the password in System Preferences > Mail, Contacts & Calendars.

To check if it's worked you will need to force a re-sync in iCal. Go to Calendar > Preferences... > Accounts > Google CalDAV > Account Information > Refresh Calendars: Every minute. Now wait a minute or so and the new events should be added. You can change this refresh rate back to your preferred setting afterwards.

This worked for me and i hope it works for anyone else who stumbles upon this thread :)