Windows 8 guest (BC) + Parallel Tools (build 8.0.18494) = BSOD 0xc000021a on boot

I've narrowed this down to the Parallels Tools installation. I can boot into Windows just fine via Bootcamp, but when booting via Parallels it fails with error 0xc000021a and is unable to auto-repair itself.

Bugcheck c000021a is apparently caused by a system-critical user-mode process crashing, causing the system to fall back into kernel mode and perform this bugcheck and memdump. I figured that since it boots fine on bare metal, the crash probably had something to do with Parallels itself - so I uninstalled Parallels Tools from the Windows instance, and poof... able to boot and run (slowly) in Parallels again. Once I reinstalled Parallels Tools, the boot errors reappeared.

These problems appeared immediately after I did a Mac system update.. what components were updated I can't honestly remember, but I'm betting that there's some sort of interplay between the Mac drivers and Parallels Tools that's not going well for the guest. Any suggestions on where to look or what to do next?

 

Update: I created a new Windows VM (with a VHD instead of a real partition) and the problem did not reproduce, so the problem also has something to do with my specific Bootcamp installation. I'm in the process of cloning the Bootcamp installation into the VHD installation to try to isolate whether it's a file issue (probably Bootcamp drivers, would be my guess) or a hardware (physical disk vs VHD) issue.