Hi everyone
Today I wanted to share a small bug you can encounter on QEMU / KVM if you are testing Windows 10’s machines. It’s something new I seen, so I wanted to discuss it.
The bug is simple to see, it’s in the Windows 10 setup at the start if you see a business login / portal that is not for your business then you must think the system UUID is probably taking one already registered online.
It’s something I never seen before, but it was reported there (or there), so it’s why I talk it.
In that case the user was seeing a login page from another business, as seen here when he used a normal ISO.

The QEMU command used to deploy the machine;
qemu-system-x86_64 -drive file=Windows.img,format=qcow2,if=virtio \
-drive file="en-us_windows_10_enterprise_ltsc_2021_x64_dvd_d289cf96.iso",media=cdrom -drive file=virtio-win.iso,media=cdrom \
-boot order=d -enable-kvm -machine type=q35 -cpu host,hv_vpindex,hv_runtime,hv_synic,hv_stimer,hv_reset,hv-relaxed,hv-vapic,hv-spinlocks=0x1fff,hv-time \
-m 32G -smp sockets=1,cores=6,threads=1 \
-device virtio-vga-gl -display sdl,gl=on \
-netdev user,id=network0 -device e1000,netdev=network0,mac=52:54:00:12:34:56
In such case to bypass that problem make sure to change the UUID, that way to make QEMU use the system UUID;
-enable-kvm -uuid $(dmidecode -s system-uuid)
In the OOBE make sure it’s offline too.
I will quote the answer from Aarad Prasad for that part;
Make sure the process is offline, by disabling your network adapter while in the OOBE process. Get an elevated prompt by pressing Shift+F10 and executing the following in powershell:
Disable-NetAdapter -Name "Adapter Name" -Confirm:$false
You may get the adapter name by
Get-NetAdapter