Mac OS X freezes when switching network locations, or network ports

Several readers are reporting repeated system freezes in Mac OS X when switching network locations. Locations are sets of network preferences that can be toggled on the fly, frequently used by portable Mac users when accessing different services in different physical locations, or by users who routinely switch between wired and wireless networks (if one network requires a manually entered IP address, for instance).

There are also reports of freezes that occur when simply switching network ports -- that is, from AirPort to Ethernet or vice versa, for instance.

Some typical reports from an Apple Discussions thread:

"Exactly the same problem here, switching from a wireless to a wired location. (No problem the other way around.) I tried enabling Ethernet within the wireless location, and the moment I applied the change, my MacBook Pro froze. "

"I use DHCP when using wireless and a manual IP address when connected to my home Gbit ethernet. Whenever I switch, I seem to have a 50/50 chance of a total freeze."

Fixes

So far, the most reliable fix we've seen for the network location switching-freeze issue is to simply eliminate all network locations and rely on DHCP connectivity -- obviously a less-than-ideal solution.

If the freezes occur when plugging in an Ethernet cable, switching to AirPort connectivity, or otherwise simply switching the network port being used try the following:

• Turn off AirPort before plugging in the Ethernet cable
• Avoid connecting or disconnecting network cables after Mac has gone to sleep -- do it prior to a sleep session.
• Perform a deep clean of system caches with a tool like Cocktail or Tiger Cache Cleaner.
• Make sure that the port you will be using at the top of the list of available ports in the Network pane of System Preferences.

Feedback? Late-breakers@macfixit.com.

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