VT-x is not available, but is enabled in BIOS

There are three common culprits for the type of error the user is seeing:

  • VT-x is not enabled in the BIOS
  • The CPU doesn't support VT-x
  • Hyper-V virtualization is enabled in Windows

Since the user already eliminated the first two possible culprits, the next step is to open a command prompt as administrator and run the following command:

dism.exe /Online /Disable-Feature:Microsoft-Hyper-V

Afterwards, reboot the PC and try VirtualBox again.


After updating Windows 10 to "Fall Creators Update" I got the same issue. I resolved it by the following steps:

  1. Enable all features under "Hyper-V" in "Turn Windows features on or off".
  2. Restart.
  3. Disable all features under "Hyper-V" in "Turn Windows features on or off".
  4. Restart.
  5. Now VirtualBox is working again and it shows (64-bit) in its list of operating systems.

When I had this problem, VMWare Player gave a better diagnostic response than VirtualBox did when I tried to create a 64-bit virtual machine.

It said that my machine had the enterprise features Device Guard and Credential Guard enabled. I suppose they became enabled when I ran MalwareBytes; I can't think of any other change I made.

VMWare Player pointed me to a page called Manage Windows Defender Credential Guard. That page has a bunch of stuff about Group Policy Manager settings and the like, which of course are irrelevant to a W10 HOME installation.

In turn, that page pointed me to the Device Guard and Credential Guard hardware readiness tool, a PowerShell tool for enabling and disabling this feature set on servers.

Running that tool in a Run-As-Administrator power shell and giving this command

 .\DG_Readiness_Tool_v3.5.ps1 -Disable -AutoReboot

took me through the process of disabling those features.

And I have virtualization capability back.