How to Fix Your Mac’s “kernel_task” High CPU Usage Bug
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macOS acting slow? Got the dreaded spinning pinwheel of death? A limited combination of hardware and software generally keeps Mac problems to a minimum.

There’s one issue that never seems to go away.

You’re not alone if you’re noticing an errant process called kernel_task eating much of your available CPU. So what is this process, and how can you free up precious resources? Read on to find out.

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 Apple’s equivalent to the Windows Task Manager — a “Ctrl Alt Delete” of sorts for managing resources and processes Activity Monitor: The Mac Equivalent of Ctrl+Alt+Delete Activity Monitor: The Mac Equivalent of Ctrl+Alt+Delete If you want to be a fairly proficient Mac user, it is necessary to know what Activity Monitor is, and how to read and use it. As usual, that's where we come in. Read More .

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 Everything You Need to Know about Your Mac's Dock Everything You Need to Know about Your Mac's Dock It's the primary way many users interact with Mac OS X, but a lot of people still don't know some of the most basic and useful things the dock is capable of. Read More for even quicker access when things start to go wrong.

How to Fix Your Mac's "kernel_task" High CPU Usage Bug activity normal

The reason for your slow computer should be evident on the CPU tab. Just click the %CPU column header to organise running processes by share of their processor usage. Anything using a high amount of processing power will appear at the top, and things 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.

You can kill any such 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 your operating system.

How to Fix Your Mac's "kernel_task" High CPU Usage Bug activity cpu usage

It’s not so much a single process, but a series of processes under one label. macOS does all sorts of things in the background, like sending and receiving data over the network, writing and reading data, 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 computer’s performance?

Quick Short-Term Fixes

Because kernel_task is basically your operating system, and killing processes is the best way to free up resources, 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. But 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 while restarting your computer.

How to Fix Your Mac's "kernel_task" High CPU Usage Bug reset smc

Instructions for resetting the SMC vary slightly depending on whether you have an old MacBook, new MacBook, or desktop computer like the iMac. Check out how to reset your Mac’s SMC here How To Reset Your Mac's SMC & PRAM – And Why How To Reset Your Mac's SMC & PRAM – And Why Sometimes your Mac will act strange for no apparent reason, and if a restart doesn't work, sometimes you'll need to reset the SMC and PRAM. Read More .

Another common cause of an out-of-control kernel_task process is Flash. Speaking from experience I’ve seen everyone’s least favorite browser extension Why Flash Needs to Die (And How You Can Get Rid of It) Why Flash Needs to Die (And How You Can Get Rid of It) The Internet's relationship with Flash has been rocky for a while. Once, it was a universal standard on the web. Now, it looks like it may be headed to the chopping block. What changed? Read More do this with Safari in particular. For a quick fix, try killing any unresponsive or thirsty tabs, or quitting the browser entirely.

Other Things You Can Try

Perhaps the most obvious fix for any OS-related issues is to update to the latest version of macOS. Simply launch the Mac App Store, head to the Updates tab, and run any outstanding Apple software updates.

Flash seems to be another cause of kernel_task issues. Update to the latest version of Flash player if you’re using a browser like Safari where Flash is not included (as it is with Chrome). While Safari is probably the best browser for Mac users, Flash doesn’t play particularly nicely with it.

How to Fix Your Mac's "kernel_task" High CPU Usage Bug remove flash

You may also have success by locking down Flash, or even removing it entirely if you’re not really using it. The browser extensions ClickToFlash and ClickToPlugin block Flash by default, with the ability to toggle it off or on.

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

Digging a Little Deeper

Others have had success in removing kernel extensions, modules of code which are able to perform low-level tasks. Also known as “kexts,” the vast majority of 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. 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 here it points to an issue with a third party kext.

How to Fix Your Mac's "kernel_task" High CPU Usage Bug kextstat

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 while third party drivers will have the developer name in them, like com.paragon-software.filesystems and ch.tripmode.TripModeNKE to name a few.

The best way to remove these is to remove the associated software. For some applications that will simply mean moving the application file to the Trash then inputting your administrator to make advanced changes. 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 hides the Uninstall option next to its settings.

How to Fix Your Mac's "kernel_task" High CPU Usage Bug paragon kext

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 applications from injecting code into Apple’s own apps, and writing to certain parts of the drive that Apple deems important to system security How to Disable System Integrity Protection (and Why You Shouldn't) 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 .

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. But if you’re at the end of your tether and you’ve tried everything else then it’s another option for you to try.

The solution stems from a blog post written by Rhys Oxenham way back in 2012. And though you’ll need to circumvent SIP, the fix still involves the same process. Rhys’ issue was related to heat management, his Mac shifting CPU focus to kernel_task in order to run low-level processes. This in turn would “cool” the system by limiting available processing power.

Another blogger by the name of Viktor Petersson wrote about his success using this method to solve his kernel_task woes. In his case, it was likely caused by a dodgy sound card. He later followed it up with updates for El Capitan and Sierra, noting the only difference now is the requirement to disable SIP.

I’ve not personally tested this fix. 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) 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. Move and backup the file relevant to your model, as described.
  5. Reboot into Recovery mode and enable system integrity protection using the csrutil enable command.

Be careful! This is a last resort fix. Attempt it f you’re struggling to get anything done due to the problem. And it persists even after reinstalling your operating system. But you have been warned. You’ll also need to repeat the process after every major software update or operating system upgrade as Apple will restore the file you moved.

Problem Fixed?

Have you managed to fix kernel_task related problems using any of these methods? Tell us what caused your issues, and what you did to fix it in the comments below.

If you’re still having problems, leave a comment and we’ll try our best to help you fix the issue.

Image Credit: Mark H. Evans via Flickr

Explore more about: macOS Sierra, OS X El Capitan, OS X Yosemite.

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  1. 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.

  2. 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...

  3. 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.

  4. 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.

  5. 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

  6. 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.

  7. 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.

  8. 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!

  9. 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 .

  10. 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

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


    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 ....

  12. 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.

  13. 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,

  14. 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.