I have a QCOW2 image (Homeassistant VM), that I ran for several months without problems.

A few days ago, I reinstalled the VM host,so I copied the image to a backup drive and now wanted to start a VM from this image.

However, it always end up hanging at "booting from hard disk" and takes up 100% load on one core.

On the VM host, I imported the image like this:

# copied from HAOS wiki
sudo virt-install --name hass --description "Home Assistant OS" --os-variant=generic --ram=2048 --vcpus=2 --disk /var/vm/hass.qcow2,bus=sata --import --graphics none 

To ensure that my host wasn't broken, I tried the same image on another machine, that I know can run VMs (virtual machine manager, using the GUI), but same result. One core at 100% and no change at all.

I even let it run over night, but it was still at this point.

One machine runs NixOS, the other Debian 12.

What could cause this? There are no errors in journalctl or /var/log/qemu.