MacBook Air 2020 (not m1 chip) fans suddenly switches on

applesteed wrote:

…

…

Although for the third question... I did startup in Safe Mode a week ago and the fans did not come up at all but as I restarted it to come out of Safe Mode the fans did come on. However, I recently deleted all my downloaded apps and that still didn't do anything.

I don’t remember seeing you mention this Safe Mode behavior. ❓⁉️

In any case, this is a strong, indicative key‼️

This indicates the following:

1. Your problem is highly unlikely to be hardware!
2. Your problem is (almost certainly) with some system or kernel extension, or some other third-party “startup” software that is being prevented from running in Safe Mode!

Unfortunately, it is all too common for people to try to «delete all [their] downloaded [or other third-party] apps»—and thinking they have succeeded—to still have myriad background “pieces” of said Apps “hanging around”, causing trouble.

This is why we, around here, always try to stress fully removing Apps according to their manufacturers’ instructions!

(In fact, just recently, I saw a comment by someone that performed a rather extensive “hunt and destroy” operation—under the guidance of the software manufacturer’s technical support personnel—in order to eliminate all the “little bits” of that manufacturer’s software.)

So. Considering this, and your apparent skill level, you will, likely, be best served by following Branta_uk’s advice:

* If Safe Mode starts and works without the fans you are probably looking for a rogue app. If you can’t identify it you might have to consider uninstalling some of your apps until the problem goes away. Then put things back and test again, one at a time to find out which one is causing trouble.

Or, better still, Branta_uk’s recommendation of «Wiping the machine and reinstalling a «vanilla OS»»:

1. Backup your Mac!
2. Wipe your Mac’s drive and install a clean Operating System (OS).
3. Don’t restore any of your third-party software, Apps, system/kernel extensions, login items, etc.!
4. Once you see that your Mac is behaving well, then install only your files! No third-party software, etc., of any kind!
5. Once you see that your Mac is, once again, behaving well, then, as Branta_uk recommended: «Then put things back and test again, one at a time to find out which one is causing trouble.»

Ok - discovery " com.symantec.mes.systemextension " is connected to Symantec AntiVirus. There is the problem. AntiVirus, Optimizers, Disk Cleaning etc are known to be big problems and are not needed on macOS. If anything, they create more problems even to the point of modifying System Files and or corrupting an otherwise perfectly working macOS.

Enough of my rate - Strongly suggest removing the Symantec Software as per the Developers Instructions right away.

Once uninstalled should see significantly better overall performance .

The only things I can think of now you have tried to remove all the downloaded software is either wipe the machine and reinstall vanilla OS before adding things back one at a time, -OR- maybe a failed temperature sensor which could activate the fan.

I think you need more advanced diagnostics and the skills of Apple Support to understand the results. Your 2020 machine should still be in warranty (and AppleCare?) so I suggest using Get Support to use your entitlement and raise a support case.

Oh... and reading your original report again, 168% CPU load is clearly impossible. Something is wrong!

applesteed:

I just read a novel “solution” (almost certainly not a general solution for all cases): «log out [of] your apple ID, restart your computer and log in [to] your apple ID again».

This particular solution sounds like it may fit the “odd” cases where the “errant” background processes seem to be Apple processes associated with various communication tasks.

It’s simple enough, that it seems worth a try, in your situation.

applesteed wrote:

Thanks both! I just have reinstalled the macOS and it still didn't do anything but I will try the other options you both have offered and I will keep in touch with the progress. Also for more information, I was advised to create a new test user to see if CommCentre would run on that and surprisingly I found it at 0%, so the problem lies on the main user where Commcentre seems to be running at 100%. Perhaps I didn't exactly delete the apps properly so the remnants of the app that causes the issue are lingering behind? But thank you for the help and I will try the other options!

Oh. I was already figuring that you «didn't exactly delete the apps properly so the remnants of the app that causes the issue are lingering behind».

However, I should have thought of the «new test user» test! 🤦🏻‍♂️

The fact that this helped, at least for the «CommCentre» process, is a good sign!

This suggests you may well be able to track down the culprit without having to go to the more drastic lengths of a wipe-n-clean-install-n-incremental-restore procedure.

Try resetting the SMC via Apple Documentation Here

Restart in safe mode, shift key immediately at startup. Let it run in this mode five to seven minutes. Restart normal mode

There could be a run-away process inhibiting things. Try opening Activity Monitor >> View >> All Processes. See if one or more applications / process is using excessive CPU or Memory. That would be a good start to track-down what is happening under the hood

Branta_uk wrote:

The only things I can think of now you have tried to remove all the downloaded software is either wipe the machine and reinstall vanilla OS before adding things back one at a time, -OR- maybe a failed temperature sensor which could activate the fan.

…

Wiping the machine and reinstalling a «vanilla OS» would also help indicate the possibility of «a failed temperature sensor» or other hardware associated cause for high fan speeds.

(Macs Fan Control can also help diagnose such. It can even be used to cause the fans to go at maximum speed.)

At this stage I think we are almost going in circles, it is time to try a different approach. Before we continue, a few questions:

* If you start from shutdown and simply enter your passcode to login then wait leaving the MacBook idle, do the fans come on? (How long is the delay?)

* If the fans don’t come on until you <do something> what have you used which may be a provoking factor? Try to get some idea which app might be responsible - start and use only one app at a time, then reboot and try something different. (Not applicable if the fans come on after reboot without any other apps)

* try a startup in Safe Mode, see if it still happens.

* If Safe Mode starts and works without the fans you are probably looking for a rogue app. If you can’t identify it you might have to consider uninstalling some of your apps until the problem goes away. Then put things back and test again, one at a time to find out which one is causing trouble.

applesteed wrote:

In that case, since we know the problem lies in the main user, what should I do to track down the culprit without erasing the whole macOS? Or should I as Branta_uk suggested and adopt into that new test user?

The easiest thing to do is to do as Branta_uk suggested: adopt that new test user account (making it an Administrative user, if it isn’t already).

Then, you can track down the issues with your former account at your leisure.

However, be careful and fully aware as you make this new user account your “home”: something you have set up, under the former user account, is causing the trouble!

If you are not careful, you can simply set up your new user account to have the same problem!

iCloud is only going to be the source from which you restored or opened a problem file. It sounds plausible that one of your MS Office document files is either corrupt or causing excessive processor load, and it might have loaded something into MS Office (like a Macro or Script) when you first used it.. It is likely this was a file you didn't use since opening a new ID, and the problem probably appeared fairly soon after you used the dodgy file so I would try to think back to which files you opened, used, accessed, etc in the few hours/day or so before you noticed the problem had reappeared.

The other thing you could try is to completely remove MS Office apps from your MacBook and see if the problem goes away. That would help confirm where the problem is coming from. This should not remove your documents (but make sure you have a backup just in case) and it is easy enough to hit the App Store and reinstall Office apps after your testing.

Thanks Halliday for your thoughts. I agree on almost every point and my disagreement is only a minor addition,

#1 Backup. I strongly recommend at least 2 backups as insurance against one failing if you know you are going to use the backup. Ideally you would probably have one backup in Time Machine, plus TWO standalone offline backups of critical user's data and documents. By standalone offline I mean something like duplicated USB flash drives, or similar which can be completely isolated after checking the required data has been protected and the backups are readable.

#2 Check carefully on the reinstall process before wiping the MacBook. I seem to have seen a few reports recently from users who have rushed to wipe, then discovered they had done more than they really intended and the reload was not as easy as expected. Apple has multiple online support docs describing the various methods. In some cases if it goes wrong, a full recovery might require a second Mac to be available so it pays to get it right first time. Basic guide examples are below, and many more available by searching https://support.apple.com

How to erase your Intel-based Mac – Apple Support

How to reinstall macOS - Apple Support