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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