OS X Lion: iCal Repeatedly Asks for Google Calendar Password
By Adrian Sutton
The one problem I’ve found when upgrading to Lion is that suddenly iCal couldn’t sync to my Google Apps Calendar account – instead it repeatedly asked for the password. I’m still not really sure what caused this, but my solution was to simply delete both ~/Library/Preferences/*iCal* and ~/Library/Calendars. You really only want to do that if you exclusively use Google Calendar. If you have local calendars deleting ~/Library/Calendars will delete them.
Once I’d done that, I re-enabled the Calendars option for the account in System Preferences, “Mail, Contacts and Calendars”, entered my password one last time and it worked perfectly.