Can't start my virtual Box machine after installing Docker on Windows

VirtualBox can't run anymore because Docker for Windows activates Hyper-V during its installation (with your permission). So you have to disable this feature again. You have to uncheck Hyper-V in Control Panel -> Programs -> Programs and Features -> Turn Windows features on or off. After a reboot, VirtualBox should be able to run again.

I had the same problem.

I just due to changing Hyper-V Launch Type using BCDEDIT.

You can try setting the launch type to Off by running the command below:

bcdedit /set hypervisorlaunchtype off

Please see this post => How to Disable Hyper-V Completely in Windows 10

i have the same problem. but after turn off hyper-V,i still can't open my virtual machine. then i upgrade virtualbox to the latest version,then virtual box works again.