kmosx: Kernel Panics ? Don't panic too !

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Last Modified: Feb 22, 2011 6:27 PM
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Hi !

This FAQ talks about "Kernel Panics" : what they are, when they are likely to occur and how to solve them.

Step 1 - What is a Kernel Panic ?


Kernel Panics are very uncommon errors that happen when Mac OS X is unable to handle a very complex problem - which, most of the time is hardware related. To know if your computer experiences Kernel Panics, just check this page.


Note : Before following the steps described in this FAQ, backup all your data. In order to do so, you may want to use a backup utility like the one that is provided with every .Mac account.

Step 2 - Solving Kernel Panics - The hardware tests



As long as Kernel Panics are often hardware related, it is always a good idea to begin with a few hardware tests. This will allow you to solve them more effectively. Here are the steps to follow :


  1. Disconnect all your peripherals, except your Apple Keyboard and mouse. Does the computer still crash ? If it's not the case, the problem is very likely related to one of your peripherals.

    • Make sure that you're using the latest drivers available for your printer, scanners, burners, hard drives... Ask their manufacturer directly if there is a known-problem or an upgrade available.

    • Check all your cables, connections ( ports ) and the devices themselves




  2. Boot from the "Apple Hardware Test CD" that came with your computer and run an "Extended Test". Does the test find a hardware problem ?

    • Call your nearest Apple Store, Apple Authorized Service Provider or Apple Authorized Reseller and have your computer checked.


    • Would you have installed some extra components ( RAM modules, modem or video cards ), remove them first, test again and, if necessary, ask their manufacturer



  3. Check your firmwares and update all of them if needed. Firmwares are the link between hardware and software. You do not directly use your computer's firmware but Mac OS X is constantly talking with it. An outdated firmware may cause some random Kernel Panics.



    • Make sure that your computer's firmware is up-to-date by browsing the Apple Care Knowledge Base


    • Keep in mind that modem cards, video and audio cards or any other extra component may need a firmware. Check their manufacturer website.





Step 3 - Solving Kernel Panics - The software tests



Would your computer pass all these tests, the problem may be software related. Here are a few steps to follow :


  1. Boot from the "Mac OS X Install CD 1" and use the Installer menu in order to open the "Disk Utility". Then, click on the "First aid" tab and repair both the drive and the privileges. Does you computer still crash ? Go to next step...

    • Would you want to use a more powerful third-party utility, feel free to do so. However, make sure that it is fully compatible with the version of Mac OS X that you're using. An outdated disk utility may in fact cause some Kernel Panics by damaging the file hierarchy...



  2. In this case, Mac OS X seems to have been heavily damaged by a software or a previous crash. You may want to re-install Mac OS X by following these steps. Then, re-install your applications carefully, one after another. Make sure that you always use the latest version available !




Step 4 - Still crashing ?



Would you still experience problems with your computer, follow the steps that are described on this page and log your Kernel Panic. Then, the best thing to do is to call Apple or your nearest Apple Store, Apple Authorized Service Provider or Apple Authorized Reseller. These logs will help them to solve the problem.

Of course, feel free to post in these forums too !



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