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

Recently I started having an issue with VT-x on my Windows 10 running on HP EliteBook. I was using Oracle VirtualBox to run some VMs on it before and VT-x was enabled in BIOS and was working fine.

I started getting VT-x is not available error every time I was trying to start any of my VMs. That started happening after I installed Docker on my machine, so I tried uninstalling it and rebooting. Didn't help.

I checked BIOS settings and it says VT-x is enabled but checking with Intel(R) Processor Identification Utility shows that VT-x is not supported and Oracle VirtualBox also doesn't see it.

There were no hardware changes and the only software change was installing/uninstalling Docker.

How can this issue be fixed?

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.