Switch between Hyper-V and VirtualBox or VMware on Windows
Let's say you've installed Hyper-V on your Windows machine and done some work requiring Hyper-V to be enabled. If you now try to start a VirtualBox machine, you won't be able to because Hyper-V is using VT-x on the CPU. To be able to run VirtualBox virtual machines again, open Command Prompt as an administrator (Start > Command Prompt > right click > Run as administrator), and execute the command below.
bcdedit /set hypervisorlaunchtype off
Then reboot the computer. When the system restarts, you should be able to run VirtualBox virtual machines again. To turn Hyper-V on again, execute the command below.
bcdedit /set hypervisorlaunchtype auto
Now reboot, and you can use Hyper-V again. To see what hypervisorlaunchtype is currently set to, use the bcdedit command without any parameters and use findstr to filter the output as shown below.
bcdedit | findstr hypervisorlaunchtype