Freezes when switching network locations/ports: Parallels to blame?

We previously reported 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).

We also noted some fixes, including eliminating all network locations and rely on DHCP connectivity (obviously a less-than-ideal solution), re-ordering ports, and clearing caches.

It now appears that virtualization software -- specifically Parallels -- may be implicated in some of these freezes.

This report from MacFixIt reader Steve has been echoed by others:

"When I had the problem of crashes when switching network locations, I found the source of the problem to be Parallels Desktop. When running at least a Windows VM in Parallels, if I switched network locations Parallels would go crazy (as verified in Activity Monitor) and eat up the cpu, either slowing the computer down drastically, or, and often, bringing my Macbook effectively to a halt, requiring a forced reboot. The problem was repeatable. When I didn't run a VM in Parallels there was no problem. The application could be running - the problem only occurred when actually running a VM in Parallels. I switched to VMWare Fusion and have not had the problem with it (nor any other problems with it.)"

The obvious, temporary fix is to exit Parallels before switching network locations or ports.

Feedback? Late-breakers@macfixit.com.

Resources