Windows 10 in BC needs repair

Discussion in 'Windows, Linux & Others on the Mac' started by Killerbob, Jan 15, 2017.

  1. Killerbob macrumors 6502a

    Joined:
    Jan 25, 2008
    #1
    I have a "Windows 10 Pro" Boot Camp installation on my Mac Pro, which I unfortunately need for work. I installed it last year and it has been working just fine until today. There was an update of sorts, and now I can't boot into Windows.

    As soon as the Windows boot is going, I get a BSOD;

    Recovery
    Your PC/Device needs to be repaired
    The Boot Configuration Data for your PC is missing or contains errors

    File: \EFI\Microsoft\Boot\BCD
    Error code: 0x000000f​

    What do I do to fix this? I have a USB stick with Windows 10 installation files, created using BootCamp Assistant from an ISO file.
     
  2. ActionableMango macrumors 604

    ActionableMango

    Joined:
    Sep 21, 2010
    #2
    Sounds like a Windows update failed part way through, leaving the system in an unusable state.

    Boot the install media, go the repair section, advanced, and roll back to the last system restore point.
     
  3. Killerbob thread starter macrumors 6502a

    Joined:
    Jan 25, 2008
    #3
    I tried that, and nothing worked.

    I eventually made a WinClone of the BootCamp partition, blew away the partition, and went back to "all Mac". Then I connected an external ThunderBolt SSD and put the WinClone image onto it. This I can now use from Parallels and can run Windows 10. I can't however, make that show up as a boot disk when rebooting the Mac.

    It works as a Parallels media, but NOT as a BootCamp partition.

    If someone could tell how to make that work, I'd be a happy camper....
     
  4. ActionableMango macrumors 604

    ActionableMango

    Joined:
    Sep 21, 2010
    #4
    Windows won't boot from an external drive.

    You can try this solution for working around that limitation, but I have no experience with it:
    http://superuser.com/questions/982577/how-to-run-windows-10-from-an-external-hard-drive
     
  5. Killerbob thread starter macrumors 6502a

    Joined:
    Jan 25, 2008
    #5
    Is that something new since Windows 10?

    I had it working just fine with Windows 8.1, installed on a proper Boot Camp partition, then copied using WinClone, and restored on an external LaCie Thunderbolt SSD.

    This worked fine for a long time, I only moved the Boot Camp internally since I upgraded to Windows 10.
     
  6. ActionableMango macrumors 604

    ActionableMango

    Joined:
    Sep 21, 2010
    #6
    Not that I know of, but I've personally never tried. I suppose you could ask twocanoes what to do.
     
  7. imacken macrumors 65816

    Joined:
    Feb 28, 2010
    #7
    No help I'm afraid, but I have the exact same problem!
     
  8. imacken macrumors 65816

    Joined:
    Feb 28, 2010
    #8
    Is there no way of doing a boot repair on Bootcamp? I really don't want to recreate all my Windows stuff. I can see all my files!
     
  9. ActionableMango macrumors 604

    ActionableMango

    Joined:
    Sep 21, 2010
    #9
    Boot to your recovery partition, recovery disk, or installation media, then run the repair option.
     
  10. MRxROBOT macrumors 6502

    MRxROBOT

    Joined:
    Apr 14, 2016
    Location:
    1011100110
    #10
    I can't offer any help with your predicament but I thought it's important to mention that Windows 10 has no problem being installed on an external drive with Thunderbolt. No hacks needed as it your sees your thunderbolt drive as internal. It's been like this since Thunderbolt was introduced.
     
  11. imacken macrumors 65816

    Joined:
    Feb 28, 2010
    #11
    Doesn't work, sadly.
     
  12. Killerbob thread starter macrumors 6502a

    Joined:
    Jan 25, 2008
    #12
    And that's exactly as I thought. I do not think I have a 2Windows on external drive" problem, but rather a BootCamp problem. I just don't how to solve it...
     
  13. ActionableMango macrumors 604

    ActionableMango

    Joined:
    Sep 21, 2010
    #13
    You'll have to repair the boot configuration data manually then.
    https://www.lifewire.com/how-to-rebuild-the-bcd-in-windows-2624508

    This is all assuming that the error message is correct and that the problem is actually the BCD.

    If you're spending a significant number of hours troubleshooting, keep in mind it might just be a lot faster to reinstall Windows. Windows 10 installs fairly quickly compared to older versions.
     

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