After installing Windows 7 using BootCamp on a 2012 MacPro with HighSierra (Beta). I booted in Windows 7 and now cannot boot back in MacOSX as the BootCamp Utility on Windows isn’t working properly. I’ve tried using the Cmd and Option key combinations to launch in Boot Selector or Recovery Mod, but neither of them work as it seams that the keyboard isn’t being detected until Windows launches. I’ve also tried removing the HDD that Windows is installed on, but that only brings a black screen with a single flashing underscore in the top left corner.

Need urgent support to get back into MacOSX to access my Business Critical applications.

  • Are you using a Bluetooth keyboard? Do you have access to a USB keyboard to try?
    – grg
    Sep 20, 2017 at 20:34
  • I am using a wired keyboard. I’ve just tried taking the clock battery off the main board, and putting it back. But it didn’t seam to make a difference. It made it worse at best. Sep 20, 2017 at 21:50
  • It would still make sense to try another keyboard & USB port.
    – Tetsujin
    Sep 22, 2017 at 18:56
  • I managed to get in by trying another wired keyboard on the front USB port on the Mac Pro. Once I got into Windows, I had to play about with the BootCamp files and got it working.... Windows HDD is now Wiped and using it as a Back-Up HDD Sep 23, 2017 at 22:57

1 Answer 1


Try something for me, if it doesn't work, ask someone else.
Restart the computer. Right after you hit the restart button, press and hold the option key until it either boots into one of your operating systems or pops up a screen in which you can switch between the two. That's how I had to switch between windows and MacOSX on my mac.

  • I have already tried it, but it automatically boots into Windows, but now that I have taken out the clock battery to reset the PRAM / NVRAM (As I cannot use the keyboard), my Windows has an error and wants me to boot into a Recovery Mode using arrow keys (But the keyboard doesn't function)... And the issue here is going back to MacOSX and wipe the Windows HDD clean to protect myself against future issues and just use Parallels to Virtualise instead. Sep 21, 2017 at 8:52

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .