I had a strange problem on my MacBook Pro Retina 15’ during the last 4-5 weeks…
My kernel_task would erratically start eating up all CPU cycles until the Macbook practically slowed down to a grinding halt.
This happened especially when I was heavily using VMWare Fusion or Video encoding and when I was working on my Thunderbolt display…
Searching the “Interwebs” I found hundreds of “magical remedies” for this problem which basically constitute the 101 of OSX problem solving:
- Repair the disk
- Login as Guest/ create new Account
- Start in safe mode
- Kill all “strange” processes with Activity Monitor and “kill” in Terminal later
- Reset PVRAM
- Replace some kexts for the Audio driver and IOPlatformPluginFamily
- Unload all LaunchAgents
- Did spindumps
- Did a clean reinstall of OSX
But the problem came back after each attempt.
I was on the verge of believing that it might be a fried motherboard when I found the solution here!
It actually is pretty stupid:
- I have my MBP hooked up under the Thunderbolt Display and stacked on top of another MBP
- Summer did arrive and we go from -10C to 35C
So the thing got too hot and kernel_task starts consuming all CPU cycles to slow down a potentially rogue process to cool the system down.
Just “unstacking” it and letting it sit and “breathe” normally, after 2 minutes kernel_task went back to normal.
So if you have the kernel_task process run wild, first and foremost try to just let it cool down before loosing hours in narrowing down the problem.