On Windows 11, you can use the "Windows Sandbox" feature to create an isolated lightweight virtual machine to test ...

If you fail to enable nested virtualization or the Enable Nested VT-x/AMD-V option is grayed out in VirtualBox, here is how you fix the problem in Windows 11/10 PC.

On Windows 11, enabling the isolated environment to test applications requires turning on virtualization at the hardware level before you can turn on Windows Sandbox.

Hmm. Ok, maybe I forget to enable virtualization in the BIOS. Oh, no, that's enabled all right. Hmm. To Google! I find some ways of checking to see if virtualization is enabled in Windows. Answer ...