Hi, I have a similar problem, my hardware does also not support the IOMMU… but I am still willing to try this OS to see if I am capable of learning at least a bit of it. I am running Qubes 4.2.0-rc3. I can see dom0 and debian-12-xfce started but if I try to start sys-net or sys-whonix I get that error of the title of the original post. The weird thing for me is that in the [Dom0] Qube manager I see that all qubes are “default (default-dvm)”. Virtualization is enabled in my BIOS. I am asking as I couldn’t find the solution after a long time search. Thanks