After successfully installing Windows 8.1 on my 2010 MacBook, running Yosemite as its primary OS, my Windows OS rebooted 5 minutes after a fresh install and now I'm stuck in the "automatic repair loop". I also get this error after trying to repair:

The drive where Windows is installed is locked. Unlock the drive and try again.

Also even after I installed the Bootcamp drivers my system was still void of this "boot camp control panel" which leads me to think this maybe a driver issue.

This is the second time I've gotten this issue so I don't think another install will resolve anything.

Is there anything I can do to stabilize my Windows OS and successfully get the Boot Camp control panel to work as well?

  • Also to install Windows 8.1 through Boot Camp I had to use gdisk and do a PRAM reset. In the meantime I think I'm going to try Parallels.
    – avery
    Apr 9, 2015 at 18:27

1 Answer 1


If you did not use the Boot Camp Assistant to install Windows, then you likely installed Windows 8.1 in UEFI mode, which neither Apple nor Microsoft support on a Mac.

If you don't want to use the Boot Camp assistant, then the trick here is to have created an empty FAT partition on the drive with Disk Utility BEFORE you attempt to install Windows. Disk Utility will create a hybrid MBR on the disk, and the presence of the hybrid MBR causes the Mac firmware to use BIOS emulation which is required for Windows to run correctly.

The use of Windows 8.1 in UEFI mode on a Mac is possible, but it's asking for trouble and you should only run it that way it if you really know what you are doing.

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