I'm using Google Calendars on more than one account.

Everything was fine in macOS High Sierra, but after upgrading to macOS Mojave, the CalendarAgent process sat at about 100% CPU, continuously.

The only way I could hold the fans quiet is by freezing it by running:

killall -STOP CalendarAgent

But that's not really a solution. All it does is prevent the runaway process from executing. Consequently, the Calendar.app client doesn't work anymore.

Anyone encounter the same problem? Any ideas on a proper fix?

1 Answer 1


Well, it appears that somehow the upgrade must have left the calendar info in a weird state, because this seems to have fixed it:

  1. Disable all Google calendar accounts (Calendar.app -> Preferences... -> Accounts).

  2. Wait for the CalendarAgent process to subside. Eventually it will; use Activity Monitor to check. A reboot may help at this point.

  3. Enable each Google calendar account, one by one: every time one gets enabled, the CalendarAgent process will get excited for a while. Wait for it to idle before enabling the next account.

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