Running Hyper-V and VirtualBox on the Same Computer
November 22, 2013 2 Comments
I recently wanted to try out a virtual machine that was pre-built for Oracle’s VirtualBox. So, I installed VirtualBox on my Windows 8.1 Pro laptop (which already had Hyper-V installed on it), configured the virtual machine, and attempted to start it up.
It failed miserably with very poor performance and frequent crashes. Examining the settings for the virtual machine, I noticed that I was unable to access the tabs that contained the Hardware Virtualization settings, including VT-x.
I knew that VT-x was configured and working on the laptop, because Hyper-V requires it, so why wasn’t VIrtualBox recognizing it?
A little research turned up the following information posted to the TechNet forums by a Microsoft MVP. It turns out that "when hyper-V is installed on Windows 8 Pro, the hypervisor is running all the time underneath the host OS, and only one thing can control the VT hardware at a time for stability. The hypervisor blocks all other calls to the VT hardware.” The TechNet discussion is found here.
In other words, Hyper-V must be turned off in order to use VirtualBox.
Further research identified a way to turn off Hyper-V. Note that a reboot is required.
Turn hyper-v off with:
bcdedit /set hypervisorlaunchtype off
and a reboot.
To turn Hyper-V back on, use:
bcdedit /set hypervisorlaunchtype on
bcdedit /set hypervisorlaunchtype auto
it may be necessary to run the command prompt as an administrator in order to issue the bcdedit command. The bcdedit command with no arguments will list the current settings, so the status of the hypervisorlaunchtype setting can be verified before and after the update.