Mac

How to Fix Your Mac’s “kernel_task” High CPU Usage Bug

Kris Wouk Updated 17-12-2019

It’s never fun when your computer starts running slowly, but it’s even worse when you can’t figure out why it’s so slow. If you’ve shut down all the programs you can and everything on your Mac still feels like it’s moving through molasses, this could be a sign of the dreaded kernel_task causing high CPU usage.

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On your Mac, kernel_task is the name given to a variety of low-level functions that allow the rest of your computer to work. This means figuring out what the culprit is can be tough. We’ve seen this a lot, so we’ve got a handful of tips to help you get rid of this problem.

Diagnosing a Slow Mac

If your Mac appears to be running slowly, is generating a lot of heat, or sounds like it’s about to take off due to high fan speeds, then you’ll want to open Activity Monitor and find out why. This is essentially macOS’s equivalent to the Windows Task Manager. Activity Monitor is a useful tool What Is Activity Monitor? The Mac Equivalent of Task Manager Learn all about Activity Monitor on your Mac and how to use it to check detailed information about your system. Read More for managing resources and processes.

You can open Activity Monitor using Spotlight: just hit Cmd + Space then start typing “activity” and it should pop up. You can also find it under Applications > Utilities, and you might want to pin it to your Dock for even quicker access when you run into major issues.

macOS Activity Monitor

The reason for your slow computer should be evident on the CPU tab. Just click the %CPU column header to organize running processes by processor usage. Anything using a high amount of processing power will appear at the top; these will move around as your computer performs various tasks in the background.

High CPU usage is generally only a problem when you’re not expecting it. It’s reasonable to expect your machine to chew up resources if you’re running a game, watching a video in your browser, or editing a video. If a single Safari tab or Mac process is using more than its fair share, that generally means something’s gone wrong.

Why Is kernel_task the Culprit?

You can kill most processes by clicking on them, then clicking on the X in the top-left corner of the screen. Unfortunately, you can’t do this for one particular process: kernel_task. The reason for this is that kernel_task is actually part of macOS.

Activity monitor kernel_task high CPU usage

It’s not so much a single process, but actually a series of processes under one label. While you’re working, macOS does all sorts of tasks in the background. These include sending and receiving data over the network, writing and reading data to the disk, and indexing new folders or disks for Spotlight search.

This process will often use a lot of your available RAM on the Memory tab, but that’s much less of a worry. The amount of RAM in use will rise and fall as required. High CPU usage, however, can bring your whole system to a grinding halt, and even result in the occasional complete system crash.

So how do you stop kernel_task from negatively affecting your Mac’s performance?

Simple Solutions for kernel_task Issues

In many cases, a simple restart of your Mac will clear the problem up right away. This isn’t a permanent long-term solution if you’ve been having this issue for a while, though. Instead, it’s a short-term fix that should provide immediate results.

Whatever is causing the spike in CPU usage may return. So if you’ve been having repeat incidents, you might want to try resetting your system management controller (SMC) too. This is easy to do and can fix a wide variety of macOS issues.

Instructions for resetting the SMC vary slightly depending on what model of Mac you have. Because it can fix so many issues, we have a full guide detailing how to reset your Mac’s SMC How to Do an SMC and PRAM/NVRAM Reset on Your Mac A reset of the SMC and PRAM/NVRAM can help any Mac, including MacBook Pro and MacBook Air, run smoothly again. Read More . It also covers resetting your PRAM, another part of a Mac that can cause multiple issues.

Other Solutions for kernel_task High CPU Usage

Perhaps the most obvious fix for any OS-related issues is to update to the latest version of macOS. Simply launch System Preferences, click Software Update, and run any outstanding Apple software updates.

Another common cause of high CPU usage by the kernel_task process is Adobe Flash. The days when Flash was essential for browsing the web are long gone, but you may still need it for a specific web app or site.

Instead of keeping Flash installed, you can use a browser like Google Chrome, which provides Flash (albeit optionally). Most likely, you don’t need Flash at all, so it’s safe to remove.

Adobe Flash Player Uninstaller Mac

If you want to remove Flash altogether, run the Adobe Flash Player Install Manager and click Uninstall.

Digging a Little Deeper Into High kernel_task CPU Usage

Some have had success in removing kernel extensions, which are modules of code able to perform low-level tasks. Also known as “kexts,” the vast majority of these extensions are installed by Apple as part of the core macOS environment. Some software will install third-party extensions as drivers, or for controlling hardware.

One quick way to check if a third party kext is causing your kernel_task issues is to reboot your machine into safe mode. To do this, restart your machine and hold the Shift key as it boots. Safe mode loads only the required kernel extensions, so if the problem doesn’t occur in this environment, it points to an issue with a third-party kext.

To dive into this, reboot your system as normal and launch Terminal. Then, run the kextstat command to see what kernel extensions are currently loaded. All Apple extensions will look like com.apple.[etc]. Meanwhile, third-party drivers will have the developer name in them, like com.paragon-software.filesystems and ch.tripmode.TripModeNKE to name a few.

macOS kextstat comand

The best way to remove these is to uninstall the associated software How to Uninstall Programs on Mac Need to uninstall programs on your Mac? You have several options! Here's how to remove programs and apps from your Mac. Read More . For some apps, that simply means moving the application file to the Trash, then inputting your admin password to allow the change.

Others may include a PKG uninstaller file you need to run. For the rest, head to System Preferences and look for any third-party preference panes. Paragon’s NTFS driver, for instance, hides the Uninstall option next to its settings.

Paragon NTFS for Mac uninstall

Starting with OS X El Capitan, Apple introduced a new security feature which broke a number of third-party modifications. System Integrity Protection, or SIP for short, stops apps from injecting code into Apple’s own apps, as well as writing to certain parts of the drive that Apple deems important to system security.

This results in better system stability, so you should see this issue less often in modern versions of macOS.

Still Have High CPU Usage? What to Do When All Else Fails

The final solution here is a bit of a risky one: removing Apple’s own kernel extensions. Doing this is not recommended. However, if you’ve tried everything else and are still seeing kernel_task causing high CPU usage, this is a solution you may want to try.

Developer and blogger Viktor Petersson has written extensively about kernel_task and the issues around it. In his case, it was likely caused by a dodgy sound card. Petersson’s initial post focused on Mac OS X Yosemite, though he later followed it up with updates for El Capitan and Sierra.

We have not tested this fix and can’t say whether or not it will work for you. If you’re interested in giving it a go, here’s what you’ll need to do:

  1. Create a backup of your Mac using Time Machine or another backup solution.
  2. Turn off System Integrity Protection How to Disable System Integrity Protection (and Why You Shouldn't) There are more reasons to leave macOS' System Integrity Protection on than turn it off, but turning it off is easy. Read More by booting into Recovery mode and running the csrutil disable command.
  3. Follow Viktor’s method. Start by finding your Mac’s model using the system_profiler -detailLevel mini | grep "Model Identifier:" command.
  4. Run the following command:
    1. cd /System/Library/Extensions/IOPlatformPluginFamily.kext/Contents/PlugIns/ACPI_SMC_PlatformPlugin.kext/Contents/Resources
  5. Move and back up the file relevant to your model. For example, if your identifier is MacBookPro8,2 you would run:
    1. sudo mv MacBookPro8_2.plist MacBookPro8_2.bak
  6. Reboot into Recovery mode and enable System Integrity Protection again using the csrutil enable command.

Again, this is a last-resort fix. Attempt it only if you’re struggling to get anything done due to kernel_task rendering your Mac unusable. This isn’t a short-term solution—it persists even after reinstalling your operating system.

Even so, you’ll also need to repeat this process after every major software update or operating system upgrade, as Apple will restore the file you moved.

Is the kernel_task Bug a New Problem?

Generally, upgrading to a new version of macOS brings new features and capabilities, but it can also introduce bugs. This is especially true on older models of hardware that are starting to push the limits. If you’re one generation away from a Mac that is no longer supported, that could mean that your model isn’t as much of a priority for Apple.

Did you recently upgrade your version of macOS? If only then did you start seeing issues with kernel_task on your Mac, that could be the culprit. If you’re not relying on new features introduced in the latest update, you may be able to safely downgrade.

Want to give it a try? We have a guide detailing multiple ways to downgrade to an older version of macOS 3 Ways to Downgrade to an Older Version of macOS Want to downgrade your Mac to a previous version of macOS? Here are several ways to revert versions if you're not happy. Read More .

Explore more about: Activity Monitor, CPU, Mac Tips, macOS, Troubleshooting.

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  1. Julie
    February 8, 2020 at 9:15 am

    I have had this problem, with kernel task taking up to 800-1000% of the CPU (sounds impossible, but it isn't!) I tried a number of the simpler solutions without success. Then I thought about trying to clean the kernel cache. I use Onyx, so it was a very simple thing to do. And voilà, no more wild fan running and stopped computer! Definitely worth a try before taking any more drastic measures. (MacBook Pro mid-2015 running Sierra 12.6)

  2. Julian
    August 16, 2019 at 2:34 pm

    I deleted the the entire folder named "IOPlatformPluginFamily.kext" that worked for me. Then I put some new thermal paste on the CPU and I monitor and have the CPU fan start up at an earlier temperature keeping it cooler, an app called Macs Fan Control. Good luck!

  3. weirdei
    May 14, 2019 at 4:30 pm

    I had this issue when I attached my LG Ultrafine monitor to the macbook via dock station. When I did it directly everything went fine.

  4. leo
    March 12, 2019 at 6:41 pm

    Do not update your mac OS. System updates are slowly killing your mac. The same applies to iOS. They say the updates are meant to preserve your system, your battery, but after updating you mac will lose overall performance.

    Here's what happened to my iphone 5S: I tried to restore a backup, but itunes refused to do because I was using ios 10.something. So I look after some information on Apple website and decided to update to iOS 12. Since then my battery lasts about 10 hours – 40-50 minutes with screen on.

    The same happened to my MacBook Air 13 after Mojave: battery charge lasts 3 hours at best an this kernel_task is consuming to much CPU and threads. Mostly because of safari.

    To make things worse, Apple doesn't allow you to downgrade anymore. I really miss my old iPhone and my old Macbook. Don't know if I'll get other again because I'm not a fashionista interested in showing off my iThings buying the new ones every year. I see macs as worktools, and I want them to last 3 or 4 years at least.

    • Alex
      August 9, 2019 at 9:46 am

      Exactly the same happens to me. I have a MacBook Pro from mid-2014 and an iPad Mini 2.

      I actually have macOS Catalina running on the mac and I've been experiencing the same things you stated since macOS Mojave. Kernel_task consumes a freaking 329.86% of my CPU (I've just checked it), and the battery takes ages to charge.

      The iPad Mini is running iOS 9.3.1 and my iPad is constantly lagging and the battery drains are constant. It's not Jailbroken.

      I use my Mac for work and I cannot afford to expend more than a thousand dollars on a computer, or buying a new iPad.

      I have lot's of important and valuable things on my iPad but I can't even make a backup to at least save them.

      I love MacBooks and macOS, but as you also said, I want things to last a few years and not having to expend thousands on new devices every year to have a decent thing to work with.

  5. Erdinc
    January 2, 2019 at 7:38 pm

    When I close Safari browser, kernel_task CPU usage is reduced to normal (mostly 1 digit %). Not only close browser app from close button, but also need to explicitly exit using right click-->exit from Safari icon at dock bar.

  6. Cassio
    October 17, 2018 at 2:50 pm

    Your tip definitely bring my old macbook late 2009 running Yosemite to life back again. Thank you for spreading your knowledge.

  7. Robert
    July 21, 2018 at 7:39 pm

    I had the same exact kernel sluggish issue on my MBP retina, 15inch, early 2013 on an 2.8Ghz, Core i7 w/ 16GB RAM. It happens when my MBP is connected to 3 Monitors via Belkin Thunderbolt 2 express Dock HD . I disconnected all display and after a few the high utilzation disappeared. After a while of stabilization I decided to place back the 2 of the 3 monitors not connected to the belkin dock and had not seen the sluggishness back. I suspect the dock is the culprit. I will check out belkin if they had any firmware update to prevent this sluggishness issue. hope this helps...

  8. Mac Zen
    July 3, 2018 at 7:38 am

    In the case of one particular 13" MBP early 2011 that belongs to a client, the issue of crippling high CPU usage was caused by an expired battery. New battery (not through Apple, but a very genuine-looking battery that I'm told is OEM) and CPU usage back to normal levels with oceans of idle time. Admittedly, I also zapped the PRAM 6 times afterwards, and that may also have resolved the issue, but I'm pretty confident it was the battery.

  9. Clean-It
    June 20, 2018 at 9:11 am

    Good advice, but you forgot something very important. Because kernel_task can be simply a process to prevent CPUs from overheating (a very aggressive and annoying way to do this) by hijacking it, you should of course clean your CPU/GPU cooler. Dust can heavily reduce the efficiency of the cooler.

    To do this, shut the Macbook down, take the bottom case of, take the two fans off with 3 screws each and use pressed air to clean the grid of the heatpipe from dust (the part near the fans). If you don't want to take the fans of, lock them by holding them lightly with your hand so that they cannot spin (they could induce voltage to the mainboard which could damage the mainboard). Work time is about 10 minutes, for me it reduced temperatures about 10 degrees C. You can also lock the fans and take a vaccum cleaner, but pressed air is much more effective for this.

    Also, a good (and as I know the only) software to control temperature and is macs fan controll (free). If your kernel_task problem is temperature related (which is likely), than you can adjust your fans in a more intelligent way than Apple did.

  10. Rod
    June 1, 2018 at 7:02 am

    My kernel thingy is at 200. As soon as I turn on my Mac the fans go crazy and my computer is super slow. What can I do

    • leo
      March 12, 2019 at 6:42 pm

      Downgrade

  11. Glen Baguley
    February 19, 2018 at 1:35 am

    I tried this on High Sierra... seems apple blocked this. Get message "Operation not permitted" . Any other workarounds?

    • Jonathan
      March 12, 2018 at 11:46 pm

      yes. through the recovery mode you can disable the SIP which will allow you to delete the file. I finally figured this out on my MBP and now works like new. Just google disabling SIP and follow the instructions. After I deleted the particular .PLIST file for my computer it worked great.

  12. bill
    December 29, 2017 at 7:18 pm

    My kerneltask is consistently jumping into the multiple-thousands of percent (1500 is not uncommon, and I've seen it over 3k) on my mid-2012 MBP. I've reset the SMC and PRAM, NVRAM and everything else I can think of to fix the "runaway" kernel CPU usage. I'm running high sierra, 8GB RAM, SSD drive and this can occur with no "applications" running. I spend a fair amount of time with activity monitor running looking at complete RAM consumption and thousands of percent kerneltask CPU usage. I'm beginning to believe this is one of Apples not subtle hints you you have to upgrade or will simply get worse and worse. Monitoring RAM usage I can get under 50M free in 5 minutes from a cold boot with no apps having been started. Everything has been pulled from startupitems, except BitDefender. I'm very comfortable on a command line to any suggestion there or otherwise, I'd love to try.

  13. Glaucio Araujo
    November 25, 2017 at 4:17 am

    Thank you SO MUCH! I’ve had an unsuccessful High Sierra update on my 2010’s MacBook Pro and reverted back to Sierra. I could not get rid of the slowness from the kernel_task and resetting the SMC DID THE TRICK! Thank you!

  14. C L
    September 28, 2017 at 3:18 am

    What happens if there isnt a file with a name matching whats listed as the model identifier on my computer in that final folder?

    • AD
      January 6, 2018 at 8:34 pm

      I have the same issue - my model identifier is iMac14,2 but there no such file....frustrating. Can anyone help?

      PS - for a practice, it tried to move/rename the one called iMac12,2 (which is listed in the system) - but it said I could not do that.

      • Jake Johnson
        August 15, 2018 at 7:48 am

        Hi, did you ever figure this out? I’m in the same position (macbookpro11.1 but no file of that name)

        Thanks, Jake

    • CAp
      August 20, 2018 at 1:53 pm

      it's actually a horrible thing because the only know solution doesnt work anymore . Apple removed the models from the folder been stuck now for several days without being able to work on a MBP15. anytime i plug in external monitors it just makes the kernel skyrock .

  15. C L
    September 28, 2017 at 3:16 am

    What happens if in that final folder, there is no file matching the name listed under model identifier? That's happening to me.

    • Jake Johnson
      August 15, 2018 at 7:48 am

      Hi, did you ever figure this out? I’m in the same position (macbookpro11.1 but no file of that name)

      Thanks, Jake

  16. carlos
    August 13, 2017 at 6:38 pm

    Hi,

    Short version :
    Dropped a glass of water on the keyboard (too long to explain how it happened)
    Dried it and didn't work.
    Opened it and dried the inside and turned on again. It worked for 2h the time I realized that the battery wasn't charging any more.
    The programs were so slow I couldn' t click the apple button to turn it off properly.
    Turned on again : same slow.
    Turned off and on again to clear SMC .. and now the macbook will just turn on for the chime then shut down.
    "Help ! I need some body. Help, anybody ! Help"

    Long version:

    I've dropped water on my macbook late 2012.
    I dryed it with the dryer and the macbok upside down as best as I could.
    When I tried to turn on it wouldn't. I thought that was it so I opened the macbook and foud somme drops of water.

    I dried it again and turned it on. It had worked so I was glad.
    I then opened several programs so the macbook would get hotter and the remaining water would boil out of it.

    2h later the maxbook was working fine when suddenly it started to go slow ... like relly slow. So I decided to turn off and on again and realized the battery was at 1 %.

    When it came on again it was still slow so much I couldn't open any thing so I turned off again (hard rebooted) and tried to clear the SMC.

    Now the computer boots for the chime sound then it shuts down completly.

    Here I am looking for help ....

  17. douira
    July 27, 2017 at 11:53 pm

    Hi, I have a similar problem: my mac has spiked in kernal_task usage especially when running CPU intensive programs (20% of total CPU time in 8 core hyper threaded i7). These spikes don't cause the mouse to jolt, just the everything else stops for a second and then continues from where it would be as if nothing had happened. These spikes happen about every few seconds but are quite irregular. This may be connected with Logitech gaming software or VirtualBoxVM being installed? idk, just seems like something that installed kexts and could maybe be causing trouble... Any help would be greatly appreciated!

    • EK
      August 25, 2017 at 4:12 pm

      I'm running an iMac with Sierra. About 6 months ago I started getting the pinwheel a lot.

      Recently, I stated using the activity monitor. It seems to show that my WiFi connection through Comcast's Xfinity is the source of my problems.

      First, the Norton anti-virus was a definite problem. The task "syndaemon" associated with Norton frequently demanded >100% of the cpu. I removed it and things improved but the pinwheel persisted associated with the "kernal_task" frequently >50%.

      I stopped keeping the Xfinity home site open in a window and for a couple days now I haven't seen the pinwheel.

  18. Srini
    June 20, 2017 at 6:34 am

    Thank you. You saved the day. Simply after running the command kextstat, the kernel_task cpu went down drastically and my system is responsive again.

    Thank you,

    • Nial Terry
      August 4, 2019 at 5:50 am

      Simply running kextstat is not going to have any effect on your system; all it does is generate a report. If there was any sort of noticeable change, it must have been something else you did.

    • Nial Terry
      August 4, 2019 at 5:51 am

      Simply running kextstat is not going to have any effect on your computer's performance; the command is a reporting tool, only. If you noticed any difference in the performance it must have been something else you did.

  19. Aalok
    March 3, 2017 at 11:55 am

    I have the same issue. and I tried all everything mention here and other blogs. now the issue is solved to a certain extent.
    But, still there is a problem. Whenever i connect to the prower, my Kernel task is going above 400% cpu usage.

    Any suggestion, what might be possibly wrong and how can i fixed it.

    (PS. I use a dell monitor will my MBP connected via mini display)

    • Jarrett
      May 26, 2017 at 6:43 pm

      I own an iMac (retina 5K, 27-inch, Late 2015) and used to have this problem (kernel_task 494% CPU, fans at full speed, very noisy). I took it to Apple and after intensive testing they found the processor to be faulty and replaced it. I've been OK for months since that.