Windows VM stuck on boot with CPU type set to host

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dbondarchuk

New Member
Dec 16, 2025
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Hi!
I am in the process of upgrading my old Proxmox server that was housing my Windows VM for gaming purposes. It had an i7-8700 with RTX 3060. It was in a large 4U case and was getting quite slow. As I wanted something smaller and a bit more efficient, I decided to upgrade to Ultra Core 265 with LP RTX 3060. I also decided to move the Windows disk to a separate NVME drive and passthrough it through to the VM directly. I cloned the disk using CloneZilla.
When the new server was ready, and a new VM with passthrough was created, I recreated EFI and TPM disk, and the VM booted successfully. But once I changed the CPU type to 'host', it stuck on the "Select boot option" progress bar with the Proxmox logo.
As it is on passthrough NVME, I was able to successfully boot into Windows directly (without Proxmox). It also successfully boots in safe mode with network in Proxmox 'host' CPU VM. I installed the latest drivers for Intel in the VM.
I tried to remove all PCIE devices from VM (except disk).

Does anyone have idea what can cause this? Thanks

P.S. It also doesn't work with CPU set to 'max' in VM. I tried `hidden=1` flag from some old posts on Proxmox forum too
 
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Thread 'VM Reboot Issue - VM stuck on Proxmox start boot option screen'

Hey All,

So this problem I've been having for a little while now is sometimes I will reboot a Virtual Machine and then it will fully shut down and come back and just get stuck 9/10ths of the way on the start boot option and a lot of times if it's say a Windows update scheduled at 12 am, i'll get in the morning at 8 am and it's still there just sitting like this.

Usually a forceful stop or reset will get it working again but I have no clue why this happens.

Another time a colleague of mine rebooted their alarm server during the day at 11 am that I'm hosting on a Proxmox Ceph cluster and...

Have a read of some this thread may help you
 
Yes, I have been through that thread, and unfortunately, nothing helped.
But today, to test, I created a new VM with CPU set to host, installed a new version of Windows on the VM disk, and it works fine. So the problem is really interesting :)
 
I have an Alder Lake CPU and using the CPU host. If I enable WSL2 or Hyper-V, Windows gets stuck on boot, just like what you experienced. To get it to boot, I have to temporarily switch to Skylake-Client-v4.
 
dbondarchuk said:
Yes, I have been through that thread, and unfortunately, nothing helped.
But today, to test, I created a new VM with CPU set to host, installed a new version of Windows on the VM disk, and it works fine. So the problem is really interesting :)
Click to expand...
I have also done that but eventually the host type will end up locked up on the boot menu like it does. Since that thread i've switched ALL my VMs over to the virtualised CPU and instead of host and haven't had any issues with the boot menu since.

Here's another thread that you may be interested in setting the CPU type to host, it seems to be very problematic

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Thread 'High VM-EXIT and Host CPU usage on idle with Windows Server 2025'

Good evening, I have been pouring over an interesting problem and it seems like I need some deep insight. Windows Server 2025 Core has much more than expected overhead.

I am testing Windows Server 2025 Core (and Desktop) on Proxmox 8.3, with all paravirtualized features enabled and the agent installed.

On the VM all virt-io drivers have been installed and VBS has been explicitly disabled. The OS is newly installed, is completely idle, with no software installed, and running idle for quite some time, so no background or startup tasks.

I have tested various combinations of cpu flags...
 
Have you made any settings for CPU-related options?

The options available for the CPU type host are limited.

Unnecessary options can cause the virtual machine to become unstable.
 
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