Hyper-V reports that the hypervisor is not running. How to start the hypervisor?

I've created and run Hyper-V guests on this machine in the past. VT extensions are enabled in the BIOS; no changes made there. I've changed my boot device order recently.

How can I ensure that Hyper-V's host hypervisor is started on Windows startup?

When attempting to start a VM, the Hyper-V Manager error shows:

An error occurred while attempting to start the selected virtual machine(s).

Failed to restore virtual machine state.

Virtual machine 'Windows 10 Tech Preview' could not be started because the hypervisor is not running.

The Hyper-V Virtual Machine Management service is set to Automatic.

I've previously run bcdedit /set hypervisorlaunchtype auto as Administrator.

No other VM products like VMWare or Virtualbox is installed.

Solution 1:

I had exactly same problem and tips by Daniel B and Norman helped me: Running bcdedit alone revealed that hypervisorlaunchtype was indeed set to off so bcdedit /set hypervisorlaunchtype auto followed by a reboot did the trick.

I am reposting their comments as an answer to preserve them.

This was caused by (unsuccessful) attempt to run Android emulator from Android Studio.

Solution 2:

Since I've tried to install Docker for Windows, I found out that my CPU just can't run Hyper-V although I could install it.

This page explains that Windows 8 Hyper-V Client (and I think Windows 10 too) requires a SLAT-capable CPU to run. To check your CPU capabilities, use the Coreinfo utility (https://technet.microsoft.com/en-us/sysinternals/cc835722) with the option -v, the '-' character indicates that the feature is missing.

Maybe your CPU lacks some features too, hope it helps !