Here's my situation:

  • I bought Win8 from the internet when it was 30 dollars.
  • I upgraded it to Win 8.1
  • I do not have a CD/DVD drive.
  • In order to install it, I created a disk partition from my 64GB SSD and placed all the installation files in there (Z:\ partition).
  • As a result, I have C:\ with 55GB for the OS to run and 3GB in the Z:\ as my Windows Installer.
  • To install, I simply booted the Z:.

Today, I turned on my computer and it got the blue screen of death with a sad face. I tried to use System Restore without any luck.

My last resort is to use Windows Refresh.

  • When I try to refresh it, my computer asks for a Windows Media (CD/USB?).
  • When I boot the Z:\ and try to refresh it, it asks me to choose which boot I want to repair. Of course, I'm going to choose the Windows 8.1 boot option. It then tells me that The drive that Windows is installed is locked. Unlock the drive and try again.

How can I unlock the Windows drive (C:) and repair it from Z:?

Note: My Windows will not start. Everytime I try, it crashes under the 0xc0000021a error and no System Restore option fixed it.

  • I assume you still get a BSOD even if you boot into Safe Mode? – Ramhound Jan 16 '14 at 18:25
  • Yes, tried Safe Mode and no luck. – Marco Aurélio Deleu Jan 16 '14 at 18:38

I managed to turn on my computer on again. With my experience about this sort of things, I know that what fixed my problem was a whole bunch of set of actions rather than just the last one. For those reading my solution, I'm gonna try and describe everything I did since the problem presented itself.

  • When starting normally, the computer will crash into the blue screen, collect data and restart
  • During restart, Windows will try to fix, fail and show a screen that says "Restart" or "Advanced Options";
  • I entered Advanced Options and got into the System Restore option, where I tried to restore to "Yesterday". The restoration then failed.
  • I repeated the process and selected an older restore point (6 days ago), which was the only other restore point available beside the one that failed.
  • The restoration was a success, but the error did not go away;
  • Since I have Z: as a Windows Installer partition (like a DVD drive with the CD on it), I booted it, and got into the Troubleshoot -> Refresh option. It then told me that "The Windows Drive was locked".
  • I restarted and booted Z: (the installation partition) and press Shift + F10
  • Execute: bootrec /fixmbr; bootrec /fixboot; bootrec /rebuildbdc;
  • At this point, CMD told me that NONE Windows Installtion had been found, so I did not had to confirm (Y or N) to the command's response.
  • I turned on my computer and went into the Advanced Options -> Troubleshoot -> Advanced Mode -> Automatic Repair

It took a while (about 10 minutes), but the computer rebooted and everything was fine.

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