I was using my laptop in Windows on Macbook Pro this morning and decided I should reboot after a software update (non-Windows).

Assuming all was fine, Windows prompted me with the "Diagnosing your PC..." and then presented me with a failure to repair my PC.

I was confused because I was just in Windows and was doing a simple reboot.

After reading, I found this answer and tried the first option

Run this command on recovery prompt:

bcdboot c:\windows

After that, I rebooted and Windows presented me with an error that the file "vmsproxy.sys" wasn't digitally signed.

I went to F8 and disabled signing verification and Windows booted just fine.

After each reboot I'm presented with this error preventing me from booting and I have to disable signing verification.

I'm not sure what this vmsproxy.sys belongs to, some searching suggests my virtual machine switch, but I'm not positive.

I have no clue how to get the proper file back, I've even ran this command with no success to fix this file:

sfc /scannow

Any ideas how to fix this?

I could disable and re-enable Hyper-V and maybe it'll reinstall, but I haven't gone that far.


If it is complaining just about this single file you could just grab a copy of the same file from healthy Windows installation. Bare in mind that it should be same version and build of Windows. You can check that by running ver command from command prompt. I am not sure which version of Windows you are running. I run Win 10 and have two versions of the file. One at this location C:\Windows\WinSxS\amd64_microsoft-hyper-v-d..s-vmswitch-netsetup_31bf3856ad364e35_10.0.14393.103_none_be69061af918233b and the other one here C:\Windows\WinSxS\amd64_microsoft-hyper-v-d..s-vmswitch-netsetup_31bf3856ad364e35_10.0.14393.0_none_b1dc374771fef683

Hope this helps

  • I really don't know if that's the only file it's complaining about or the first file it checks and errors on. I will try to find another build of Windows 10 that has this file and replace it and backup this other one first of course. – ScottN Oct 5 '16 at 21:30
  • I updated my answer with locations. Also provide the Windows build. Maybe I could help – Vita Oct 5 '16 at 21:35
  • I could zip it and drop it somewhere – Vita Oct 5 '16 at 22:03
  • Replacing the file from those folders didn't work, Windows wouldn't boot saying there was an error with the .sys file. I decided to try uninstalling Hyper-V and I was able to reboot fine without disabling driver signing. Thank you for your help. – ScottN Oct 5 '16 at 22:24
  • No problem, but why the downvote, please? I believe it was valid suggestion and effort and research was put in the answer. It's possible I dont understand downvote enough as i am new here. I though it was for like really stupid answers. Thanks and sorry if i am wrong – Vita Oct 6 '16 at 15:59

I went to Programs and Features > Turn Windows features on or off and un-ticked Hyper-V and let it uninstall. This allowed me to boot into Windows without disabling driver signing checks.

I have no need for Hyper-V at the moment, so I haven't re-installed, but I assume re-installing Hyper-V will properly setup and not have this issue again.

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