Periodically the CPU on my iMac Mid-2015 running OS X 10.10.4, gets used almost exclusively by:

  • launchd: ~70%
  • fseventsd: 12%
  • UserEventAgent: ~40%
  • opendirectoryd: 20%
  • notifyd: 12%

I have tried quitting programs (e.g. Chrome, Outlook etc.) and no apparent process seems to be the culprit. It seems to occur once an hour (at least it has done it 3 times in the last 3 hours) and each episode lasts ~10-30minutes. It does not appear to be reproducible with any action that I take.

If I open Console.app, in system.log, there are many repeated errors, such as:

Aug  6 16:29:11 DREWGEHRYW13 com.apple.xpc.launchd[1] (com.google.keystone.user.agent[60455]): Service setup event to handle failure and will not launch until it fires.`

These errors are not generated the entire time when this behavior is occurring, but it seems that they are written every few minutes (even when Chrome is closed).

In System Log Queries -> All Messages : There aren't any recent messages

Also, possibly related, I have experienced 2 kernel panics in the past week caused by launchd (or processes launched by it), but I will limit this question to solely the CPU issue for now.

What is causing this and how do I fix this?

  • Logs do not lie => google. Though, assuming that your iMac is using 4 cores then there still should be plenty of processing power left.
    – fd0
    Aug 6 '15 at 21:11

Today, I checked Chrome and it states that

Version 43.0.2357.65(64-bit)
Update failed (error: 12)

It appears that my version is out of date by about 3 weeks. So I believe that Chrome was periodically trying to frantically update and would subsequently fail. I followed the recommendations of Google and attempted removing the appropriate files, but my version of Chrome would still not update.

I ended up uninstalling Chrome by dragging the icon from Applications to the trash and removing ~/Library/Google and /Library/Google (not sure why it is here also...). I reinstalled Chrome and it appears that I now have the most up to date version of Chrome (44.0.2403.103) and I have yet to experience any of those errors or cooking of my cpu. I have been at my desktop now for 4 hours, so hopefully this issue has been resolved. I'll also see if I experience anymore kernel panics, hopefully these issues were related and both are resolved.

  • This fixed the kernel panic problems. It is now 3 months later and I have yet to have another one. Nov 13 '15 at 12:22

This is not a complete answer, but may be a partial solution.

I've been seeing high CPU and memory usage from UserEventAgent, and the only fix that I found after much searching was to disable Notification Center. It's quite possible that only part of Notification Center is the problem, or one particular app's notifications, but I haven't had the time to troubleshoot that yet.

To disable Notification Center, do these two commands in Terminal:

launchctl unload -w /System/Library/LaunchAgents/com.apple.notificationcenterui.plist
killall NotificationCenter

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