Mac OS X 10.2.5: some USB hubs may cause kernel panics

John S. wrote us today to detail a problem he was having with his iMac G3/400 after updating to Mac OS X 10.2.5. It seems that after the update was installed, his iMac was repeatedly experiencing kernel panics about 10 minutes after booting. Unfortunately for John S., he came across the explanation after he decided to completely wipe his hard drive and reinstall 10.2.5 and found his iMac continued to experience the same repeated kernel panics. As a public service, we are pointing out this AppleCare Knowledge Base Document at John’s request:

Mac OS X 10.2.5: Some USB Hubs May Cause Kernel Panic

Article ID: 25440
Created: 4/11/03
Modified: 4/18/03

TOPIC: After updating to Mac OS X 10.2.5, some USB hubs may cause kernel panics a few minutes after starting up.

Symptom: A kernel panic may occur a few minutes after starting up in which case you would be prompted to restart. This only occurs with certain USB hubs attached to the computer. The following information would appear in the panic.log file (/Library/Logs/panic.log):

“Unresolved kernel trap(cpu 0): 0x300 – Data access”
“…Kernel loadable modules in backtrace (with dependencies):

Products affected:
– Mac OS X 10.2.5 Update
– some third-party USB hubs

Solution: Disconnect the USB hub. This is a temporary workaround. Apple is investigating the issue and will update this document as more information becomes available. Note: Not all USB hubs are affected by this issue.

Link to the Knowledge Base Document here.


  1. MacNN provided a fix for the Apple-acknowledged Mac OS X 10.2.5 USB bug. Apple hasn’t posted a fix for the solution just a work around. The problem lies with the file IOUSBFamily.kext which is updated to version 1.9.8 with OS 10.2.5.

    Downloading version 1.9.7 from the following link and replacing the new one in the System – Library – Extensions folder then restarting will fix the problem.

    I haven’t used this fix, so I don’t know if it will work, but it’s worth a try if you really need to use your USB hub.

  2. Why not just make a backup copy of your 10.2.4 /System/Library/Extensions/IOUSBFamily.kext bundle (from Finder) someplace, and then restore it from single-user mode after rebooting into 10.2.5 for the first time?

  3. Killed my G4 Quicksilver. I did a total rebuild (took the chance to partition OS9 off this time from jaguar). Will now back-up my entire OS for just this – thought only MS did these sort of OS updates.

    Learnt the hard way!

    (have USB hub in my iiyama vision master pro 451 monitor and use a wacom tablet).

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