virtualbox.org

Help! It works really well a week ago. I don't know what happened now. I reinstall everything now even the file.

Please provide a VM log file. Make sure the VM is fully shut down, then right click it in the manager UI. Select "Show Log" and save "VBox.log" (no other file) to a zip file. Attach the zip here.

Please See Attachment

Hyper-V is enabled. See HMR3Init: Attempting fall back to NEM (Hyper-V is active).

It has solved the problem.

Virtual Based Security, Hyper-V, Core Isolation are already turned off beforehand.
I guess turning Hyper-V off manually doesn't really mean already turned off in the system even restarting the device.
That cmd stuff works really well.

Thank you @scottgus1 and @mpack!

Great! Glad you're up and running.

Lots of Windows services can use Hyper-V, and toggling the Windows Features checkboxes very often doesn't cover them all. The command line is the silver bullet.