Always Need To Have A Proper Parallels Shutdown
I had this problem and several similar problems and read many discussion boards and tried many different things until I came up with a workable plan. Parallels customer service was no help at all - ZERO. Other users and discussions like this one were helpful and then just trying different things until I figured a fix that works, etc...
The short answer is (1) once you get this error you are screwed. There is no way to recover from it and you must redo your boot camp partition with a fresh install, etc.. (2) Parallels is a very buggy/quirky program at best. When it functions properly it is truly amazing. However, lots of little things can make it snag. So if you understand this and are willing to work with it having this understanding then there are some long, pain in the ---, ways to get around some of the issues such as this. (3) Read below on how to prevent this from happening again.
I can't tell you why this particular problem arises but I can tell you one way to get around it and avoid it.
THE GOLDEN RULE of PARALLELS: When running Parallels using a Boot Camp partition running windows - NEVER, NEVER, NEVER natively boot up to your boot camp partition until you are absolutely positive 100% you had a proper shutdown after using parallels.
If you do this then you will never hurt your boot camp partition.
What is a proper shut down? There is only one acceptable proper shutdown when running parallels: start menu --> shut down. Windows shuts down and parallels flips to the long on screen for the VM. Anything different is an improper shutdown - period. And if you try natively booting to windows boot camp following an improper windows shutdown you will almost certainly corrupt and destroy your boot camp drive.
So to do to get around this? It is time consuming and a pain, but this is what you need to do. Natively Boot to Mac OS. Once Mac is booted, run parallels again (might have to create a new virtual machine, just depends). Parallels will try booting Win/BootCamp VM and in the process the blue screen running scan disc will come up and say windows didn't shut down properly and scan disc will check for errors. THIS IS IMPORTANT _ LET IT DO THIS. DO NOT TOUCH ANYTHING. Following scan disc windows should boot and come up properly. Once, windows boots up in parallels then shut it down properly. On parallels windows shuts down properly, then it is safe to natively reboot to your Bootcamp drive.
Example...
Every time I install Parallels (updated or install fresh) and then run the virtual desktop for the first time it automatically installs the Parallel tools and drivers, etc... This goes well and following installation of the tools and drivers the computer (meaning windows inside parallels using your bootcamp drive) wants to restart.
This seems to go well until the virtual machine actually tries to restart. I am not sure why but restarting the VM through windows start button --> restart always makes my machine freeze on restart - always! What works for me is to go to start button --> shut down. Once the system shuts down then just manually restart. I have now problems when I do this - never (knock on wood). The problem with the restart is not the initial shut down, this almost always goes fine, the problem is following shutdown when the computer tries to automatically restart - always freezes. It freezes the VM and it freezes my Mac. This is may be the only program that ever freezes my Mac. Anyway, after the freeze I have to do a manual hard button shutdown and reboot. This is a problem since VM tried to reboot windows and crashed it recognizes this as an improper shut down. If I were to go directly to a native BootCamp - Win boot up at this time it would fry and corrupt the boot log (or something like that) so that now boot camp will not boot correctly and there is no way to fix it except to reinstall the OS. I speak from lots of trial and error before I figured this out, etc...
NOW - if following the shutdown and subsequent automatic restart the computer freezes on a black screen and locks up everything (the VM, my Mac, everything freezes - one of the few things that will lock up my mac) requiring a hard button restart, then boot to MACS OS. Run or Reinstall parallels - boot up windows through parallels, let scan disk run, etc...and eventually windows will open in parallels. If this doesn't work try creating a new VM and if this doesn't work reinstall parallels (over the current copy). Do what ever you need to do to get parallels up and running and then do a proper shut down. What every you do do not natively boot to windows bootcamp until you have achieved a proper shutdown through the parallels system.
There are many different ways parallels and/or windows can cause itself to freeze or not shutdown properly. Regardless the cause the same principal applies you must go back and startup parallels, boot up windows using parallels, let scan disk run if necessary, and then shut windows down properly in parallels. Once a proper shutdown has been achieved then you are safe to natively boot to your win bootcamp drive.
Hope this is helpful, and prevents this from happening to others.