Virtual Machine could not be started because the hypervisor is not running

Hypervisor is not running – blaming BCD

I’ve recently been hit with the “could not be started because the hypervisor is not running” error.  I’ve attributed it to my new Windows Server 2012 install which is set to dual boot with my Windows 8 Pro install. The error goes on to give 3 explanations of why this is. The first two options didn’t apply as my hardware supports virtualisation and the BIOS had the settings enabled.  I know it supports virtualisation as it was working before the server installation.  I remember having to modify the BCD to get my system to play nice between Windows 8 and 2012 due to a linux partition I’ve subsequently removed.
My awesome powers of deduction led me to believe Option 3 was the thorn in my side.  Fixing that problem was made reasonably difficult thanks to shoddy documentation from Microsoft. Over the last few months I’ve noticed this as a recurring pattern, Microsoft’s documentation is somewhat lacking compared to how it used to be around 5 years ago.  I’m guessing a big organisational shift is responsible.

Hypervisor is not running – the solution

bcdedit /set hypervisorlaunchtype auto

If you have the required hardware and its enabled in the BIOS then the above command should fix your “could not be started because the hypervisor is not running” issues.
You don’t need to specify {current} when using the set command. I actually found it throws an error rather than setting the value if you pass across {current}.  You can check the parameter has been set by running the following command.

bcdedit /enum

Under the bootloader that has an identifier of “{current}” you should see the value at the bottom of the list. Reboot your machine and your virtual machines should now be working.
As a word of warning, don’t go playing with the “hypervisordebug” parameter in the BCD as I did. I discovered the USB keyboard and mouse no longer worked when the PC got to the login screen. Annoying. Thankfully I could remote in to it and delete the debug parameter.
Microsoft have made things more difficult by replacing boot.ini with this BCD functionality. Their lack of easy to find, good documentation makes things harder than it should be to fix anything other than trivial “how do I change the background picture” questions.

source: http://astutelogic.com/could-not-be-started-because-the-hypervisor-is-not-running/