Q: Sierra causing excessive fan operation
After installing Sierra 10.12 the fan on one of my MacBook pro's is running excessively. Activity monitor shows a process "secd" as using 93%of the CPU. Tried to use the force quit and it comes right back. On my other MacBook the activity monitor shows the "secd" as 0% CPU and it has no fan issue.
MacBook Pro with Retina display, Mac OS X (10.1.x)
Posted on Oct 2, 2016 11:21 AM
Had the same thing happen on a 2011 MacBook Air running 10.10.5. The problem appears to be with syncing the iCloud Keychain. Found the solution on Reddit:
Go to System Preferences/iCloud, click Keychain "on", then click "Cancel". Process "secd" stopped immediately, and fans ramped down.
I personally never use iCloud Keychain, so it was not turned on by default. I would guess that if yours was already turned on, toggling it off and then back on would have the same effect.
Posted on Oct 6, 2016 3:25 PM