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Jochen K

macrumors member
Original poster
Aug 29, 2014
44
0
Hi,

while I have the famous kernel_task problem, I choose here to open a new thread. I have done everything I can do without exchanging hardware ... immediately after boot the fans are at maximum -- no program running --; opening a video or a simple game makes kernel_task go to between 600 and 1800 (!) percent cpu usage, so utilising 18 cores where there are eight. I have a MacBook Pro (2017) with the maximum configuration. Before upgrading to the totally broken High Sierra, it was not a problem to play 3 movies, run windows and linux in virtual machines, and playing a demanding game on a setup with two external monitors. (If anyone wonders: this makes no sense of course; I just wanted to know how well the machine performed.)
Upgrading to High Sierra broke all this Even now -- writing this with TextEdit -- fans are at full speed, kernel_task at 400% (no external hardware attached.)
BTW, dual booting into Windows produces none of these problems. Videos, rather demanding games, on an external Monitor run smoothly. Fans are quiet.

Now I see no other possibility than to give this MacBook to "repair". I am a resident of Germany, so this MacBook is fully protected by warranty (its about 7 months old.)
Of course, Applle is not interested in any laws as long as they may be to their disadvantage.

So, perhaps someone here has tried to have a MacBook repaired in a similar situation. Is there a possibility that a "repair" fixes the problem? I ask in quotation marks, since probably there is no hardware problem.

So as a second question: is it possible to downgrade to Sierra?


Any help is much appreciated

Jochen Kaiserswert
 
Reboot your machine and use internet recovery with these keys held down:

Shift + Option + Command + R

This will allow you to re-install Sierra provided your MacBook Pro shipped with it.

You’ll definitely want to backup and important data, as you’ll have to wipe the drive. You’ll also have the option to ditch APFS if you so choose. Use disk utility first to erase the drive, then re-install macOS.
 
kernel_task consuming large amounts of CPU commonly points towards a third-party kernel extension that is probably not compatible with the version of MacOS that’s running.

Upgrade all your kernel extensions to one’s that support High Sierra, or uninstall them.

You mentioned running VMs, so you have at least 1 third-party kernel extension installed and running on there.
 
I am pretty sure the problem is with some third-party software you have installed... as others have suggested, perform a clean install of your machine and check whether the issue persists. This could still be a hardware problem, so run the apple hardware test beforehand just to be on the safe side.
 
You'd be surprised what sort of issues third party apps may cause in macOS. So, I'd first test it out with a complete disk wipe and a fresh and latest OS without third party apps. Then I'd install an app that I suspect is a culprit (especially if it installs some system extension).

And yes, it's possible to downgrade to Sierra. There might be a number of ways, but the one I did was I'd download Sierra from the store, create boot install USB media / disk from it, then boot from it, wipe the internal disk and install.
 
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