Background processes periodically eat up my CPU time on OS X 10.10.4, Yosemite

Solution 1:

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It appears that my version is out of date by about 3 weeks.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.

Solution 2:

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