Previous 1 2 3 Next 39 Replies Latest reply: Dec 2, 2015 11:18 PM by lodgechad
SteWilliams Level 1 (0 points)

My MBP has randomly started acting weird.


Symptoms are:


Running VERY slow.

Cooling fan constantly (although not running hot as far as I am aware) - fan kicks in during boot seq

Activity Monitor showing kernel_task eating circa 200% of CPU constantly.


There are no external peripherals connected to the Pro

I've not installed any 3rd party software recently (or at least within a week prior to the issues starting).


I've included a screenshot of the activity monitor Screen Shot 2012-10-07 at 11.55.56.png

As you can see, the kernel_task process is using a lot of cpu.


I've tried a SMC reset which didn't help at all.


Has anybody got any other suggestions?

Thanks in advance.

MacBook Pro (15-inch Mid 2010), OS X Mountain Lion (10.8.2)
  • clintonfrombirmingham Level 7 (30,000 points)

    Quit the process (it will restart) and keep an eye on it. kernel_task will fluctuate but shouldn't get above 13% or so of CPU %.



  • SteWilliams Level 1 (0 points)

    You can't quit the kernel_task process...

  • clintonfrombirmingham Level 7 (30,000 points)

    Oops - that's right - PID 0. Best thing that I can recommend is a restart. I've no idea why kernel_task would be consuming so much of your CPU...



  • SteWilliams Level 1 (0 points)

    Ha no problem, wasn't sure if I was missing something re: quitting it,


    I've restarted about 20 times now, but still no joy.


    Looks like a genius bar appoitment is needed, unless anyone can suggest anything else?



  • clintonfrombirmingham Level 7 (30,000 points)

    Maybe one of out 'local' genius's will come along... if not, then, yes, I suppose it's time to schedule a trip...



  • dmdimon Level 3 (840 points)

    there are background defragmentation hidden inside kernel. Also there are a lot of other disk activity inside kernel - paging, other similar tasks. Also MacOs encryption/decryption is also a part of kernel. So chances are that if you have damaged filesystem, FileVault encryption and encrypted paging file in some combination - you can get to this digits of load on kernel task.

  • SteWilliams Level 1 (0 points)

    Appreciate your input dmidimon, but I'm not an advanced macbook pro user. Is there anything that you can tell me in layman's terms to try to diagnose whats causing the kernel to be so intense on the CPU useage, and what can be done to fix it?

  • dmdimon Level 3 (840 points)

    1) do you have encryption enabled? Filevault, paging, something else? May be some third-party antivirus software? Compressed filesystem?

    2) boot from recovery partition, repair boot drive and repair permissions on it.

  • Linc Davis Level 10 (192,186 points)

    These instructions must be carried out as an administrator, if you have more than one account.

    Launch the Console application in any of the following ways:

    ☞ Enter the first few letters of its name into a Spotlight search. Select it in the results (it should be at the top.)

    ☞ In the Finder, select Go Utilities from the menu bar, or press the key combination shift-command-U. The application is in the folder that opens.

    ☞ Open LaunchPad. Click Utilities, then Console in the icon grid.

    Make sure the title of the Console window is All Messages. If it isn't, select All Messages from the SYSTEM LOG QUERIES menu on the left.

    Copy the text on the line below:


    and paste it in the Filter text field. Do you see messages like this:

    SMC::smcHandleInterruptEvent WARNING status=0x0 (0x40 not set) notif=0x0

    The timestamps of those messages (if any) indicate the times, since the log was last cleared, when the processor was being throttled because of high temperature.

  • SteWilliams Level 1 (0 points)

    Linc Davis: Again, thanks for taking the time to read my post and reply. I did as you said and there were no results when filtered on smcHandleInterruptEvent. I've done a screenshot just so you can see that I was doing it all correctly:


    Screen Shot 2012-10-07 at 16.31.26.png


    Any other suggestions guys?


    Just so you are all aware - rebooted into the Recovery Partition (where the fan was still constantly running at highspeed, but was unable to check figures on teh activity monitor as it's disabled as far as I'm aware?).


    I repaired the normal boot partition, and all other partitions as well. Still no change at all.




  • dmdimon Level 3 (840 points)

    can thermal throttling be a cause to 200% load?

  • Linc Davis Level 10 (192,186 points)

    can thermal throttling be a cause to 200% load?



  • Linc Davis Level 10 (192,186 points)

    Please read this whole message before doing anything.


    This procedure is a test, not a solution. Don’t be disappointed when you find that nothing has changed after you complete it.


    Step 1


    The purpose of this step is to determine whether the problem is localized to your user account.


    Enable guest logins* and log in as Guest. For instructions, launch the System Preferences application, select Help from the menu bar, and enter “Set up guest users” (without the quotes) in the search box. Don't use the Safari-only “Guest User” login created by “Find My Mac.”


    While logged in as Guest, you won’t have access to any of your personal files or settings. Applications will behave as if you were running them for the first time. Don’t be alarmed by this; it’s normal. If you need any passwords or other personal data in order to complete the test, memorize, print, or write them down before you begin.


    Test while logged in as Guest. Same problem?


    After testing, log out of the guest account and, in your own account, disable it if you wish. Any files you created in the guest account will be deleted automatically when you log out of it.


    *Note: If you’ve activated “Find My Mac” or FileVault, then you can’t enable the Guest account. The “Guest User” login created by “Find My Mac” is not the same. Create a new account in which to test, and delete it, including its home folder, after testing.


    Step 2


    The purpose of this step is to determine whether the problem is caused by third-party system modifications that load automatically at startup or login.


    Disconnect all wired peripherals except those needed for the test, and remove all aftermarket expansion cards. Boot in safe mode* and log in to the account with the problem. The instructions provided by Apple are as follows:


    1. Shut down your computer, wait 30 seconds, and then hold down the shift key while pressing the power button.
    2. When you see the gray Apple logo, release the shift key.
    3. If you are prompted to log in, type your password, and then hold down the shift key again as you click Log in.


    Safe mode is much slower to boot and run than normal, and some things won’t work at all, including wireless networking on certain Macs.


    The login screen appears even if you usually log in automatically. You must know your login password in order to log in. If you’ve forgotten the password, you will need to reset it before you begin.


    *Note: If FileVault is enabled, or if a firmware password is set, or if the boot volume is a software RAID, you can’t boot in safe mode.


    Test while in safe mode. Same problem?


    After testing, reboot as usual (i.e., not in safe mode) and verify that you still have the problem. Post the results of steps 1 and 2.

  • dmdimon Level 3 (840 points)

    not vice versa? Like high load - high temp - thermal throttle - lower load?

    Or you mean that actually there are 400% load and throttling drops it to 200?


    edit - I'm really interested. I'd send you private message on this instead of posting here if forum allows this...

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