Dear Aunt TUAW: My Mac had a kernel panic. Now what?

Dear Aunt TUAW,

My Mac has been experiencing kernel panics. I managed to grab an error log. Now what? I'm not sure how to use this to figure out what's going wrong... Please help!

Your loving nephew,

Esteban

Dear Esteban,

The preponderance of the time, kernel panics are hardware related and not software. Looking at the error log can help you figure out what issue may be causing it.

Look for the last loaded and last unloaded kernel extensions as well as the items named in the extension backtrace. They can provide good indication of what's going wrong.

For example, you might see the following. Here, the issue seemed to have been with a FireWire Drobo system.

    last loaded kext at 266503428590760: com.apple.driver.AppleFireWireStorage 3.0.1 (addr 0xffffff7f80920000, size 16384)   last unloaded kext at 266064709148465: com.apple.driver.StorageLynx 3.0.1 (addr 0xffffff7f808ce000, size 8192)

Or you might see the following trace, which was tied into the local USB system. Notice how the names of each item here gives you a sense of the role. IOKit is responsible for many of your system's device drivers. Names like IOUSBMassStorageClass and AppleUSBComposite tell you that you're probably working with USB issues.

    Kernel loadable modules in backtrace (with dependencies):            com.apple.iokit.IOUSBMassStorageClass(2.0.4)@0x593bd000->0x593c6fff               dependency: com.apple.iokit.IOSCSIArchitectureModelFamily(2.0.5)@0x7ba000               dependency: com.apple.iokit.IOUSBFamily(3.1.5)@0x596000               dependency: com.apple.iokit.IOStorageFamily(1.5.5)@0x7d3000            com.apple.driver.AppleUSBComposite(3.0.0)@0x953000->0x956fff               dependency: com.apple.iokit.IOUSBFamily(3.1.5)@0x596000            com.apple.iokit.IOUSBFamily(3.1.5)@0x596000->0x5bdfff

Kernel panics aren't limited to hardware. For example, emulators can also cause kernel panics. VirtualBox can be quite nasty this way.

If you pinpoint the cause of your issue (emulator or mass storage), you can usually work through the problem yourself. If not, you may want to book an appointment to take your unit to the Genius Bar or to an Apple Authorized Service Provider (ASP).

Hope this helps!

Hugs,

Auntie T, who thanks cousin Josh Carr for his assist on this write-up

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Dear Aunt TUAW, My Mac has been experiencing kernel panics. I managed to grab an error log. Now what? I'm not sure how to use this to...

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Samantha

I just got a new iMac after Apple replaced my Early 2011 MacBook Pro for a hardware sleep issue. When I added my 8GB of RAM from the MBP into the iMac, I started having Kernel Panics....I eventually tried just the 8GB of RAM and that worked flawlessly, so I added the 4GB of stock ram back into the system. Bam, More panics. I eventually replaced the original 4GB of RAM with the 4GB that came in my MBP when I got it back in March of last year.

Haven't had a problem since.

February 16 2012 at 11:02 PM Report abuse Permalink rate up rate down Reply

Katalina

OK. I have to comment here.

This is pendantic. The post was useful, and I will add two additional points:

1. A kernel panic on a new Mac is serious, serious business. Do not ignore it. Take it to an ASP right away (Apple store or apple authorized service provider, keyword being authorized here.) Anything that you mention and get a case number for is covered under the warranty period.
2. the RAM point is excellent. Both Macs and PCs can kernel panic (or BSOD in Windows case) due to bad RAM.

December 09 2011 at 12:12 AM Report abuse Permalink rate up rate down Reply

cgrsmkr9

Yes, there is a grammatical error in my original post. ;-)

December 08 2011 at 10:05 PM Report abuse Permalink rate up rate down Reply

macattorney

I'd say that about 80% to 90% of the time kernel panics are due to a hardware problem. In order of likelihood, that problem is usually:

- bad third party RAM
- a problematic USB hub
- a peripheral that your Mac doesn't like for some reason (sometimes just a poorly attached cable, or a bad cable, is the problem)

If you have very recently added new software, especially something that alters the system at a low level, such as anti-virus software, or something that changes the look and/or function of the Mac interface, I would suspect that first. Uninstall that software and see if things get better. (This type of software typically requires an uninstaller to completely disable. Just dragging the application, or the application's folder, to the Trash won't disable it.)

If that isn't it, I would restart the Mac with the Shift key held down (invoking a Safe Boot, with all kernel extensions disabled) and see if the problem goes away. If it does, the Kernel Panics are probably due to a software problem. It it doesn't, the problem is most likely hardware related.

If you suspect a hardware problem, the next thing that I would do is to shut down your Mac, uninstall all peripherals other than the Apple-supplied keyboard and mouse, restart and see if that helps. If it does, you can re-attach one peripheral at a time, restarting each time, until you isolate the offending peripheral.

If that isn't a solution, I would remove all third-party RAM and see if that fixes things.

December 08 2011 at 9:54 PM Report abuse Permalink rate up rate down Reply

Jesse-Douglas Mathew

"kernel panics are hardware related and not software"
...
"Kernel panics aren't limited to hardware."

Umm... Kernel panics are a failure of the OS to address hardware. It can indicate hardware problems, but more often than not you can solve it by reinstalling the OS. That doesn't mean it's "hardware related and not software." The kernel is software. I wouldn't refer to something you can solve with a reinstall as "hardware related and not software."

December 08 2011 at 5:58 PM Report abuse Permalink rate up rate down Reply