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Level 1

16 points

High CPU and battery drain in Sierra for CalendarAgent, and CalNCService

Since upgrading to Sierra (from Yosemite) I've been plagued with high CPU usage by these two processes. They seem to be on a schedule, so my battery life is only a few hours and overall CPU utilization in Activity Monitor looks like this:

I've tried everything I could find to alleviate this problem. I've turned off calendar syncing from every account (I have both iCloud and Google). I turned off notifications and removed all widgets for everything. I deleted the calendar cache, and even the entire calendars directory (~/Library/Calendars). I've looked in the console app for bad logs related to these processes and find no errors (but lots of normal looking activity).

Reboots do not help.

If I remove calendar sync for all accounts, boot to safe mode, reboot to regular mode again, then the CPU drops for a while. Even if I add back an account for syncing, it does the initial sync and then CPU drops and is stead with low utilization. But then after a while (a few hours) I notice the high CPU again.

At this point I have only iCloud calendars syncing, not Google. So I know that's not the root cause.

One final note, I did "upgrade" my iCloud notes when prompted to the newer notes after upgrading to Sierra. It feels like that was the point I noticed the problem, but I can't be sure it wasn't already happening as that was pretty soon after the Sierra upgrade.

Is anyone else seeing this?

Any help is appreciated.

MacBook Pro (Retina, 13-inch, Mid 2014), macOS Sierra (10.12.1)

Posted on Dec 2, 2016 1:20 PM

Best reply

V8Fun Author

Level 1

16 points

Posted on Jan 23, 2017 6:04 AM

Ok, I have as close to a permanent solution as possible. The issue seems to be caused by some trigger I have not yet identified, but it might have something to do with a combination of connecting/disconnecting an external monitor and going into sleep mode. The less often I do those things, the fewer times this issue returns.

To resolve the problem when it happens, I have to de-select "contacts" from both of my google accounts. Then wait for the CPU to settle down to near-zero. Then I can re-select both accounts. That jumps the CPU for a few minutes while it synchronizes, but after that it's steady and low until the next time the issue returns.

At this point I'm performing this process less than once per week, so it's tolerable. Still, it would be nice if Apple would figure this out and get it resolved. But with the few number of views and replies on this thread, I suspect it's totally unknown to them.

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