Over the weekend, I attempted to reconfigure some of the drives in my Hyper-V server at home. Note that I said “attempted”. I ran into hardware issues and ended up having to revert back to my old configuration – but somehow in all of this – I broke my system disk.
Specifically it would not boot any more.
This did not phase me because I knew that the excellent startup repair tool in Windows would soon have me up and running – which it did.
But I was surprised to find that when my system did finally boot – none of my virtual machines started up. When I tried to start the virtual machines manually, I was informed that the hypervisor was not running.
After scratching my head for a moment, I realized what had happened. Startup repair had rebuilt my boot configuration data store to get my system up and running. But it did not know that Hyper-V needs to have some specific settings enabled in the boot configuration data store in order to start the hypervisor.
I quickly opened an administrative command prompt and ran the following command:
bcdedit /set hypervisorlaunchtype auto
After that I rebooted the system and successfully started my virtual machines.