Mac OS X 10.3.x: Kernel panics upon location change

Yesterday we covered a reader report from Rob Tillyard that his PowerBook G4 has recently been experiencing kernel panics when switching between Network Locations (via the Locations submenu of the Apple Menu or the Network pane of System Preferences). Since then we've received corroborating reports of this issue from many MacFixIt readers.

The common threads we've been able to identify thus far -- based solely on those readers who actually provided system information -- are as follows:

• Mac OS X 10.3.2 -- earlier versions of OS X do not seem to be affected.
• PowerBook or iBook with AirPort card installed.

In addition, the following seem to be factors in this issue; however, unlike the above characteristics, these may not be representative of every reader who sent in a report:

• Switching from a Location with a primary AirPort connection to a Location with a primary Ethernet connection. (We've also had a few reports of the opposite transition, or of switching between Ethernet and modem. However, in almost every case, the Locations between which the user is switching use different network interfaces.)

• Waking the PowerBook or iBook up from sleep just before switching locations. Steve Ferry writes, "I've had the same problem on my 15" albook running 10.3.2 and my daughter is having the same problem on her ibook. It seems to be associated with waking from sleep and changing locations."

• Having an Ethernet cable plugged in before switching locations. Kay Mathiesen notes: "I was having the same problem with a kernel panic after switching Network Location. I had my Powerbook connected via Ethernet to a DHCP Server. The Location I was switching to was a fixed IP Address with a fallback to an Airport connection. The Kernel Panic happened when I switched while still having the Ethernet cable plugged into my Powerbook. When I unplug the cable before switching, everything is fine."

• Perhaps related to the previous item, starting the Powerbook or iBook up with an Ethernet cable connected. Brad Jordan writes, "I have similar problems with my 12" PowerBook when I go from my home airport setup to the church I where I work and hook up to the ethernet network. When I start the computer, I get a dialogue window saying I must restart my computer. I don't have the same problem going from there back to my airport network at home. Only when I first hook up to an ethernet network. I've tried switching the order that the computer looks for a connection, but I still get the same thing."

• Switching to or from a static IP address. Reader "Caesar113" reports, "I don't have problems when changing locations in general, but if it enables an interface with a static IP, then I get a kernel panic." Similarly, reader "lorenzen" writes, "This comment about the static IP address is right on. In my situation, I mostly use Wi-Fi, but I do have a static ip address configured for my home network. At work I plug in to a wired network (with access to a wireless). If I plug in the ethernet cable before waking my powerbook, I get a kernel panic. If I wake it before plugging in the ethernet and then change the location, it works fine."

Beyond that, details are difficult to pin down (mainly because readers didn't provide us with the same variables). Some users report that the problem began after installing the iSync 1.4 update, others claim it was predicated by installing the iChat 2.1 beta, whereas others claim it started after installing the AirPort 3.3 update.

Workarounds Reader Aaron Ciesar reports that he's found a cumbersome, but effective workaround for this issue if you normally shut down your PowerBook or iBook:

"The following steps have allowed me to boot and switch locations without crashing:

1. Unplug all network hardware and cables from TiBook.
2. Boot normally.
3. Switch locations.
4. Plug in the needed network hardware and cables.
5. Connect as needed."

Directory problems? One MacFixIt reader, Stefan Bracke, confirmed this problem but noted that after using TechTool Pro 4 to repair the directory structures on his boot volume, the problem no longer occurred.

Security Update 2004-02-23 fixes the problem? Aaron Ciesar also reports "It appears that the Security Update 2004-02-23 for Panther Client 1.0 has resolved this issue so far. Don't know why, all I know is I forgot to unplug my hardware during the reboot and I did not crash. I am still testing if this issue is resolved."

Confirmations of, or comments on, our observations? Different experiences? Please drop us a note at Late-breakers@macfixit.com.

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