On my macbook pro 2019 I'm running into this issue, where the infamous kernel_task starts blocking my computer after a couple of hours.

I know that many people are experiencing similar issues for many different reasons, but none of the approaches I've researched so far seem to work for me. So I really hope you can help me.

  • Typically I'm working for a couple of hours using basic stuff like Zoom, Chrome and my programming IDE and everything seems fine. No lags etc. Macs Fan Control is showing the following measurements:

enter image description here

  • Then, after 4-5 hours suddenly my whole computer gets very laggy. After checking the Activity monitor, I can see that kernel_task is taking up 100-300% CPU percentage.
  • This kernel_task process seems to be a system strategy to block CPU usage and prevent further heating of the hardware that could potentially cause damage.
  • This happens instantly after 4-5 hours of normal work. I do not run extra programs. The temperatures are still at ~60-65°C.
  • I can stop the lagging, if I close almost all programs. But as soon as I open up some basic programs again (Zoom, Chrome) it starts lagging again

I'm now wondering on how to further investigate this issue and identify the cause of the problem:

  • While Macs Fan Control is showing that the fans run at max speed, I don't feel very much air coming out of the macbook case. Maybe the fans don't work properly or are dirty?
  • Can you tell me why my macbook decides to start kernel_task if the CPU and GPU temperature are at ~60-65°C? This doesn't seem too hot to me.

Things I've tried:

  • Making sure the laptop is placed on a good stand.
  • Unplugging all devices including monitors, power supply etc.
  • Resetting SMC

EDIT: Cleaning the fans actually solved my issue!

1 Answer 1


65° isn't excessively hot, but it is warmer than it ought to be at idle, & would cause the fans to ramp up. Mine is at 40° right now doing not a lot. A 2019 isn't particularly old, but if you haven't blown the dust out of it in the past year, now would be a good time to do it. I do mine every 6 months & it really makes a difference to its idle temperatures.

  • Comments are not for extended discussion; this conversation has been moved to chat.
    – bmike
    Commented Apr 4, 2022 at 17:17

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .