Can't run games on host machine while Hyper-V is running

Hi

So, I just made a W10 VM with Hyper-V and it's running fine (I only assigned it 1 core and 1.5GB of memory). The VM is running a background process that consumes nothing, it's basically idling.

Now I go back to the host machine and I can't start any game. None. They all crash/freeze with a black screen as soon as I open the exe. Ofc they all ran fine before. I closed the "screen" window of the VM, I only have the Hyper-V Manager with the VM in the background. WTF? I don't get it. I assume Hyper-V is taking up the GPU or something? Only games don't work, other programs are fine. Yet GPU usage in the task manager is 0%. CPU usage 5-10% and memory 52% (I have 8GB, all the games I'm trying to run are old enough, 4GB left should be plenty). Any ideas?

How about filling out your "System Specs". It would help everyone in helping find a solution to your issue.

Marvo said:

I don't get it. I assume Hyper-V is taking up the GPU or something? Only games don't work...

I'm not a gamer, but I do use Hyper-V a lot.

What you may not be aware of is that with Hyper-V enabled, even without any VM running, your host windows is running virtualised too.

Kari said:

Type 1 Hypervisors like Hyper-V must be started before operating system is loaded. Even the host OS runs then on top of the Hypervisor...

Personalization possible pre-activation in VMware, not Hyper-V. Why? - post #2

... Because of this, Hyper-V reserves part of the GPU for virtualization even if it's not used and this reduces your gaming performance.

The Real-World Impact of Hyper-V on Gaming - CPUs, Motherboards, and Memory - Linus Tech Tips

...or in your case, seemingly kills it.

You may find this tutorial by @Kari useful and informative, Method two allows you to have a choice at boot of running with the Hyper-V hypervisor enabled or not. You can then run without Hyper-V when you want to run games.

Run Hyper-V, VirtualBox and VMware on same Computer