SONOMA 14.4 Kernel_Task CPU usage extremely high

I have a 2019 27" iMac with SONOMA 14.4 OSX updated a few days ago.

And I think the issue start to occur after the update.

My Kernel_Task would consume my CPU load up to 60-70%.

Restarting my iMac would flush the memory and everything will be back to normal until I open up any programs like Safari or Adobe Bridge or Photoshop.

The issue would persist even after I closed the program for 30 minutes; Kernel_Task would run high.

If no program is opened, everything would be fine.

I have tried a few trouble shooting method, including creating a new account, did a disk First Aid, the issue would persist.

While the only most affective method is to put my iMac to Sleep mode, it would seem to flush the memory and my CPU load would be back to single digits until I open up another program, the the problem would come back.

I felt this is a bug in SONOMA 14.4 perhaps? Because I think I have experience similar issues before until a new OSX was released.

Does any one have similar issues? or any suggestions?

iMac 21.5″, macOS 10.14

Posted on Mar 24, 2024 5:41 AM

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Posted on Apr 11, 2024 7:32 PM

Issue finally resolved, but here is the brief recaps.

Before I installed SONOMA 14.4 my iMac 2019 was running perfectly fine.

I only have Adobe Photoshop and Lightroom Class running, and occasionally watch Netflix or run some FB games.

Because I do run process a lot of stuff through Adobe from time to time, so I would have my Task Monitor open at all time to monitor my CPU or Memory pressure.

Immediately SONOMA 14.4 was installed, I noticed when I run FB game “Kernel_Task” would run over time, but I do not detect any fan noise.

I Googled up what “Kernal_Task” is, I found out it is a program that controls the cooling fan. So I noticed my iMac would get really hot by touching the back of my unit.

I tried to restart or even shut down to let it cool for a few times, it didn’t work, “Kernal_Task” will stay running extremely high, and my iMac hot.

Until I finally realized if I put it down to “Sleep Mode” it would reset the “Kernel_Task” issue, but it only resets it, not fix it.


I followed the instruction from Apple Online Help from an advisor, I have ran it through Safe Mode, and eventually format the whole thing with a fresh clean MacOS the issue still persist. So finally I contacted Apple Support again, they advise that I need to contact a Senior Advisor, and which lead to an appointment to bring my unit in for a physical check up.


At the check up, they determined the fan is faulty, and it needs to be replaced.

After a week and some money spent, I got my unit back, restarted it via TimeMachine, ran a few test to and so far it looks like it is working fine now. It still runs a bit hot, as I can still feel quite a lot of heat venting from the unit, but at least the Kernel_Task is not running at 70% of my CPU.

I think my situation was, the update somewhat killed my fan, so instead of notifying me what could the the issue, SONOMA is running over time try to initiate the fan.


I am happy I was able to fix it, but I still think that SONOMA 14.4 some what trigged the problem.


The point I wanted to make is, I have very simple and clean Mac setup. I kept plenty of space available on my HDD, I don’t have any VPN, Mac Cleaner program installed, that could cause the problem. I have unplugged all external Hub, printer accessories during my trouble shooting, so it was not caused by fault external devices.


Possible cause of the issue combining my personal experience and what I found online with who has similar issue, and spoke to people with the same issue:

  1. Updating to SONOMA 14.4.1 “could” fix the issue. My friend had the same issue on his MacBook with M1 chip, after updating to 14.4.1 it is fixed.
  2. SONOMA 14.4 is a massive update, so it requires a lot of CPU processing, which probably triggered the overwhelming work on my fan, and eventually killed it. This is my case. So the only solution is to replace the fan.
  3. SONOMA 14.4 has many compatibility issues with either hardware of software, which cause some kind of conflict in programming, and SONOMA is stuck at a loop trying to correct it.
  4. SONOMA 14.4 is not an efficient MacOS, it requires a lot of more CPU usage, or cause more hardware heating, so if you have an older unit, either the fan needs cleaning or the fan is not working efficiently, the program is unable to resolve the issue by software correction, instead it is telling the fan to run faster, harder, but in this vicious cycle, it just cause your computer to run even hotter until something fails. So probably the best solution is to get your unit cleaned up or get a hardware check, because your fan is probably dying or dead.


I still think the culprit is SONOMA 14.4, and maybe as a conspiracy Apple is trying to force you to upgrade to a newer unit, or maybe Apple has just got more MS and releasing more half baked software and have the consumer to test their program for them. I can’t really say, but for the future, I will definitely delay my updates unless it is totally necessary.

In the past, I had faith with Apple, updating whenever I could, and never had an issue, and my iMac could usually last for 5-7 years with no problem.

Surely, with more program update, and especially with AI advancement, my computer is running much slower as it would be in the past, but it would still be useable. I mean, I was still using my 10 year old MacBook Air during my iMac downtime.

Apple do make good products, and I love their eco system, that’s why I have not switched, but I would be cautions with their updates now, since I don’t know wha it’s their business strategy now a days.


And most importantly, do make Backup frequently, TimeMachine is still one of the best backup system I have every seen. My system was 99% functional, with only the exception of Loupedeck require re-installation.

I already was prepared for the worse case scenario I would need to get a new unit, but with my TimeMachine backup, at least I would still have all my work in tack.

42 replies

Apr 7, 2024 9:19 PM in response to DsTg1015

Immediately after any software update you will see increased fan usage as the CPU is running hotter due to Spotlight reindexing the newly installed files and many times you will see photo analysis processes spike with new object detections on your pictures.


I think it is difficult to point to any update that would cause this failure, but if your fan is destined to fail it is going to be noticed after an update.


Thanks for the update and please follow up after you get your fan replaced.

Jun 11, 2024 4:53 PM in response to 1_Yaw

Sad to say, if you’re here, SOMETHING has killed your fan. There doesn’t seem to be a software fix. As I wrote earlier, I’ve been using Macs since the mid 80s and never had a fan die.

You can try calling Apple Support and ask for an exception because Sonoma update caused the problem and see what help they can be. But it seems likely you need to replace the fan.

Mar 25, 2024 1:45 AM in response to DsTg1015

DsTg1015 wrote:

"What you describe could be Lack Of Empty Space on the drive."

Actually I have at least 25% of free space, and I freed up some more thinking it was lack of free space, too.
So I have over 30% of free space on my 1TB drive.
And I had not used more drive space since the issue started, while only thing I could think of is it probably start to happen after I updated to SONOMA 14.4.
I have contacted the Support Advisor, they sugguested running through Safe Mode to see if it persist, if not I'll have to reinstall my MacOS, which I really don't like to do that.
I have searched the web and found that quite a few people on different device has similar problem (search for SONOMA CPU heating issue).
I have seen other solves including stop Refreshing Wallpaper, and restart SMC twice, which I will try to see if that works.

You have the options laid out before you


Your choice

Apr 6, 2024 7:26 AM in response to KoshAlwaysHere

KoshAlwaysHere wrote:

As vanilla as possible. I only have VPN, latest version. EtreCheck said, internal disk slow. Disk Util reports no issues. It's >10% free, not geat, but I have tonnes of RAM and never had disk swaps… no issues like this ever before and no changes except recommended OS upgrade. It reports apps with high usage, not true, only Kernel Task >1000%. report below, if it fits. Any help appreciated.

<EtreCheck report, 29 min to run.log>

This computer has basically Run Out of Empty Space


Keeping, even as little as 20% of 499.96 GB would translate into 99.8 GB of Empty Space


Available Space is basically Purgeable Space which has been outline in an earlier posting


Through in maybe 4 or more External Drives hanging off this computer


And SSD too slow - SSD is showing poor performance which could be a sign of hardware issues with the drive.


Then of course the computer will take Runtime: 29:51 for the Etrecheck Application to run


Size: 499.96 GB


Free: 43.03 GB

Available: 58.35 GB

Apr 6, 2024 9:41 AM in response to KoshAlwaysHere

KoshAlwaysHere wrote:

Sincerely, thanks for replying… Odd because, I've always found that drive to be satisifyingly fast… until 14.4
Guess I'll just have to keep deleting files until Sonoma feels better. What choice do I have?

One of the reasons a drive that had 150GB free on it not long ago is suddenly "full", appears to be… the Apple TV app has been adding movies to my internal drive, instead of the external drive where it's supposed to keep all media files. I'm bound to find more issues like this - hey, painstakingly re-add those files to your media apps and see if the app puts them in the correct place this time.

Wow, imagine if that drive dies. I wonder if MY computer will let ME boot from an external drive? I feel so safe.

Maybe the drive has hardware issues. Maybe MacOS has hardware issues??
Sonoma trashed my Time Machine drive, just kept filling it up until it "failed" (what happened to deleting old backups, or at least warning a drive is getting full?), and wouldn't let me do anything but copy files off it. Naturally, the drive has been working fine since I reformated it.
I guess that's what passes for disk management, these days. Be thankful it didn't trash your data, just keep buying new drives, even when there's nothing wrong with the old ones, you're welcome.
And yes, I can have 7 drives connected to the iMac when I'm working on a project… hence the Intel iMac, the tragic iPads that pass for iMacs these days… just have to keep hoping, eventually Apple Silicon gains basic desktop class I/O capabilities. I liked it better when Apple made computers.

Welcome


FYI


Running 1 M1, 1 M2 and 1 M3 machines.


All were running Sonoma 14.0 through to and now Sonoma 14.4.1


None of them experience any of what has been outlined in above reply


But then, tend to keep at least 25% of the Total Internal Drive Capacity as Truly Free Space


As for Media Files - those I keep on an external drive and without any issues there either

Apr 7, 2024 11:19 PM in response to Mac Jim ID

My Mac ran hot for almost a week after I updated it to 14.4, and I repeated try to troubleshoot it, freeing up as much space as possible.

Even after I format it, and re-install the MacOS, the heating problem persists for days.


Yes, maybe the fan is already bound to fail, but I didn’t have this issue before the update, so it just make it odd and hard to isolate the problem from the update.

Apr 11, 2024 10:02 PM in response to DsTg1015

Glad you got your issue resolved. The fan is now the only moving part in the computer to fail other than the keyboard. The HD is now a SSD drive without moving parts and previously a major failure point. As stated already, with any OS update you will see increased CPU usage from spotlight indexing and Photo Analysis from updated algorithms. If the fan is going to fail, it will most likely be after an update where this increased CPU cycles causes more heat and increase fan usage. During normal use, the fans on a MacBook Pro will run very little if at all. You can run Apple Diagnostics and there are 3 error codes related to the fans that will show up if there is a failure. I do think it would be much more convenient if an error message would pop up on the screen when a fan error was detected, but so far that is not the case.


I think it is far from a conspiracy and more of a situation like you said where we are putting more demands on our processors that require a greater dependance on the fan. More so than was ever needed before. The fan is just becoming the weakest link in our systems and it is ironic that $10 part can now bring down a system costing over $1000.

Apr 20, 2024 7:44 PM in response to DsTg1015

For those that aren't certain an OS update can kill a fan…


- only on a particular model of iMac

- I certainaly didn't notice any more fan usage than the usual, after the update


…14.5 Beta (23F5059e) is no help. >1000% CPU for kernel_task persists


kernel_task only goes berserk once I try to do anything. It will sit for hours doing nothing, but as soon as I activate a web page, try to play music, type text… it hogs more than 10 cores, to make actually using the Mac impossible.


Still haven't run a test to see if fan is working (it takes a minute to get a Print dialogue, running Handbrake just for giggles, hasn't been a priority). Will report back if I get around to it.

Apr 6, 2024 6:14 AM in response to DsTg1015

As vanilla as possible. I only have VPN, latest version. EtreCheck said, internal disk slow. Disk Util reports no issues. It's >10% free, not geat, but I have tonnes of RAM and never had disk swaps… no issues like this ever before and no changes except recommended OS upgrade. It reports apps with high usage, not true, only Kernel Task >1000%. report below, if it fits. Any help appreciated.



Apr 6, 2024 9:30 AM in response to Owl-53

Sincerely, thanks for replying… Odd because, I've always found that drive to be satisifyingly fast… until 14.4

Guess I'll just have to keep deleting files until Sonoma feels better. What choice do I have?


One of the reasons a drive that had 150GB free on it not long ago is suddenly "full", appears to be… the Apple TV app has been adding movies to my internal drive, instead of the external drive where it's supposed to keep all media files. I'm bound to find more issues like this - hey, painstakingly re-add those files to your media apps and see if the app puts them in the correct place this time.


Wow, imagine if that drive dies. I wonder if MY computer will let ME boot from an external drive? I feel so safe.


Maybe the drive has hardware issues. Maybe MacOS has hardware issues??

Sonoma trashed my Time Machine drive, just kept filling it up until it "failed" (what happened to deleting old backups, or at least warning a drive is getting full?), and wouldn't let me do anything but copy files off it. Naturally, the drive has been working fine since I reformated it.

I guess that's what passes for disk management, these days. Be thankful it didn't trash your data, just keep buying new drives, even when there's nothing wrong with the old ones, you're welcome.

And yes, I can have 7 drives connected to the iMac when I'm working on a project… hence the Intel iMac, the tragic iPads that pass for iMacs these days… just have to keep hoping, eventually Apple Silicon gains basic desktop class I/O capabilities. I liked it better when Apple made computers.

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SONOMA 14.4 Kernel_Task CPU usage extremely high

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