Calendar gives error for Gmail Account: 403 CalDAVAccountRefreshQueueableOperation
I'm having the same problem. I'm also operating Yosemite (10.10.5)
Saw the solution below for Sierra elsewhere, but it didn't work for me.
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This problem appears to be caused by corrupted Calendar caches and it occurs in macOS 10.12.2 Sierra as well.
The easiest way to get rid of this problem is to:
Quit Calendar
Open Activity Viewer and Quit &quot;CalendarAgent&quot;
note, using QuickLook on any calendar item in the Finder will
relaunch CalendarAgent which needs to be not running at step 3
Delete ~/Library/Calendars/Calendar Cache
Delete ~/Library/Calendars/Calendar Cache-shm
Delete ~/Library/Calendars/Calendar Cache-wal
Launch Calendar
Calendar will read the information from the surrounding data folders and files in ~/Library/Calendars/ and recreate the caches cleanly.
If for some reason the files listed to delete re-appear before you launch Calendar, it means something is triggering the system calendar operations. Try quitting all of your applications and starting at step 2 or logging out with the &quot;Reopen windows when logging back in&quot; unchecked, then logging back in.
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