macbook woes

[handcyclist]

MacBook Air 2013
High Sierra with all updates

Works fine for a few hours, then CPU goes into overdrive, gets hot and fans run - everything slows to a crawl.

Activity Monitor reports that the item using all the processing power is 'kernel_task'.

Only cure is to Shut Down and Restart.

Works temporarily, then starts over doing it again with same symptons and same 'fix'.

Any MacGuru ideas?

[Pickled Onion]

Er, top google hit for kernel_task: https://support.apple.com/en-gb/HT207359

So you need to find what was happening *before* that.

[handcyclist]

Okay ...... so at the 1st sign of running hot I look at the Activity Monitor and the thing using all the CPU power is kernel_task. Because it's hot. Leaving it alone won't cure it.

Before it runs hot all is normal. Browser 2-10%, all other stuff minor. How can I tell what kicks off the CPU heat/kernel-task issue?

[Jaded]

it’s either software or hardware. So eliminate some software issues first. Have you ever done a fsck?

Close the machine down and restart it holding CMD and s

When the gushing white text has finished there’ll be two lines of text with /sbin/ in them
Type the first one exactly (includes fsck) in and let it run. If it says the file system was modified, run it again. If not, type the second line in exactly (includes ‘mount’)

Download Malwarebytes free and run it.

That’s probably enough for just now!

[ian]

What happens when you leave it with no applications running? And are there any items that run on startup (those unhelpful helpers)? Do you use Flash?

You can look at Console, it's a bit difficult to decipher, but sometimes gives up clues. I'd check à la Jaded that's there's not a disk problem. It probably won't hurt to reset the PRAM and SMC (follow the instructions for your model).

[handcyclist]

Thanks both - will try these tips and report back ....

[JulesP]

Before trying those options, I'd start by starting in safe mode (https://support.apple.com/en-gb/HT201262) and leaving the Mac running to see if it still happens. If not, then it suggests software is the culprit.

[Jaded]

Agreed, that's a good suggestion.

[handcyclist]

Thank you - I tried it in Safe Mode as suggested and all well so ....... after a lot of poking and proding and deleting, it seems it was the Flash extension in Firefox repeatedly trying to load something or other under 'CP web content'. Chucked that out and all seems to be well. For now.

At least now I know where to look - thanks again for the help.