VirtualBox suddenly returning Hyper-V errors, despite hyper-v being disabled

Question

I've encountered a recent issue in VirtualBox. It's recently started giving me errors such as: VT-x is not available(VERR_VMX_NO_VMX). On another one of my virtual machines it says: Raw-mode is unavailable courtesy of Hyper-V. (VERR_SUPDRV_NO_RAW_MODE_HYPER_V_ROOT).

The issue though, is that I had Hyper-V completely disabled. I had to forcibly disable it in CMD, as doing it the "turn windows features on or off" way, refused to work and windows would say it was "unable to complete my changes" after restarting. So instead I used a CMD command to disable Hyper-V. After this my virtual machines worked fine up until I started getting these errors as of recently.

I have no idea what set it off, I even ran a powershell script to check and it shows that the CMD command I used to disable hyper-v worked. So I'm not sure why I'm getting hyper-v related errors, despite me having it disable, as well! I even checked to see if I had virtualization enabled in my BIOS and I have that enabled as well! If anyone has any suggestions, as so far I have been unable to located one, that doesn't pertain to disabling Hyper-v, as I've already done that.

Answer 1

Could be device/credential guard:

To disable Device Guard or Credential Guard:

Disable the group policy setting that was used to enable Credential Guard. On the host operating system, click Start > Run, type gpedit.msc, and click Ok. The Local group Policy Editor opens.

Go to Local Computer Policy > Computer Configuration > Administrative Templates > System > Device Guard > Turn on Virtualization Based Security. Select Disabled.

Go to Control Panel > Uninstall a Program > Turn Windows features on or off to turn off Hyper-V.

Select Do not restart.

Delete the related EFI variables by launching a command prompt on the host machine using an Administrator account and run these commands:

mountvol X: /s

copy %WINDIR%\System32\SecConfig.efi X:\EFI\Microsoft\Boot\SecConfig.efi /Y

bcdedit /create {0cb3b571-2f2e-4343-a879-d86a476d7215} /d "DebugTool" /application osloader

bcdedit /set {0cb3b571-2f2e-4343-a879-d86a476d7215} path "\EFI\Microsoft\Boot\SecConfig.efi"

bcdedit /set {bootmgr} bootsequence {0cb3b571-2f2e-4343-a879-d86a476d7215}

bcdedit /set {0cb3b571-2f2e-4343-a879-d86a476d7215} loadoptions DISABLE-LSA-ISO,DISABLE-VBS

bcdedit /set {0cb3b571-2f2e-4343-a879-d86a476d7215} device partition=X:

mountvol X: /d

copy %WINDIR%\System32\SecConfig.efi X:\EFI\Microsoft\Boot\SecConfig.efi /Y

bcdedit /create {0cb3b571-2f2e-4343-a879-d86a476d7215} /d "DebugTool" /application osloader

bcdedit /set {0cb3b571-2f2e-4343-a879-d86a476d7215} path "\EFI\Microsoft\Boot\SecConfig.efi"

bcdedit /set {bootmgr} bootsequence {0cb3b571-2f2e-4343-a879-d86a476d7215}

bcdedit /set {0cb3b571-2f2e-4343-a879-d86a476d7215} loadoptions DISABLE-LSA-ISO,DISABLE-VBS

bcdedit /set {0cb3b571-2f2e-4343-a879-d86a476d7215} device partition=X:

mountvol X: /d

Note: Ensure X is an unused drive, else change to another drive.

Restart the host.

Accept the prompt on the boot screen to disable Device Guard or Credential Guard.

from: https://kb.vmware.com/s/article/2146361

Answer 2

As per https://techcommunity.microsoft.com/t5/Windows-Insider-Program/Windows-Defender-System-Guard-Making-a-leap-forward-in-platform/td-p/167303 you can turn off Core Isolation in Windows Settings->Update & Security->Windows Security->Device Security->Core Isolation Details->Memory integrity: off

There's also a registry key you can change if the option is greyed out on your system: HKLM\SYSTEM\CurrentControlSet\Control\DeviceGuard\Scenarios\HypervisorEnforcedCodeIntegrity\Enabled

Turn that off and reboot the computer and it should be working again