I love Parallels on my MacBook Pro and Coherence is very cool, albeit a bit quirky. Last night after Windows Update ran I was unable to successfully boot my WinXP image. Turns out a lot of others have had similar problems and an excellent solution can be found on the Parallels Forums. The problem entails from rebooting Parallels Desktop (build 3036 Beta) while in coherence mode with an external monitor connected. Upon reboot, I received the dreaded BSOD (Blue Screen Of Death)
with the error: PAGE_FAULT_IN_NONPAGED_AREA. The solution is to set the screen resolution to what it was prior to the reboot. I was able to do this by:

  1. Boot in safe mode
  2. Uninstall Parallel Tools
  3. Reboot
  4. Change to the correct resolution (for me this was 1920×1200)
  5. Re-install Parallel Tools

Another solution is to change the resolution after booting in VGA mode, although I did not test this; see the Parallels Forum thread for details.

If there is a problem uninstalling Parallel Tools, remove the registry key
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnce\ParallelTools (or something similar to ParallelTools) and try again. You can also boot in Last Known Good Configration and uninstall.

Thanks to Mike Mulligan for his solution.

UPDATE: New Beta 3094 now available!