Windows Server 2022 on Proxmox: UEFI, VirtIO and the missing disk

The installer shows no disks because Windows has no VirtIO driver. Machine type, firmware, and the snapshot to take before anything else happens.

The first machine in a hybrid identity lab is a Windows Server that will become a domain controller. Creating it takes ten minutes, and there is exactly one moment where a first attempt reliably stops: the installer reaches the disk selection screen and shows nothing at all.

Licensing, before anything else

The VM

Setting	Value	Why
Machine type	q35	Modern chipset, PCIe
BIOS	OVMF (UEFI)	Required for Secure Boot and a modern install
EFI disk	on `local-lvm`	UEFI needs somewhere to store variables
SCSI controller	VirtIO SCSI single	Paravirtualised, far faster than emulated
Network	VirtIO	Same reason
CPU type	host	Exposes the real instruction set instead of a generic model
vCPU / RAM / disk	4 / 4–8 GB / 64 GB	A DC with directory sync is comfortable here

VirtIO devices are paravirtualised: they exist to be fast, and the price is that the guest needs a driver for them. Windows does not ship one.

The disk that is not there

The fix is to load the driver during setup, which means having a second ISO attached before you start:

Attach the virtio-win ISO to the VM as a second CD drive, alongside the Windows ISO.
At the empty disk screen, click Load driver.
Browse the virtio ISO to vioscsi\2k22\amd64 and load it.
The disk appears. Install normally.

After the installation

Install the QEMU guest agent from the same virtio ISO. Without it, Proxmox cannot shut the VM down cleanly or report its IP address.
Set a static IP. A domain controller must not get its address from DHCP.
Set the hostname before promoting to a domain controller — renaming afterwards is possible but not something you want to do.
Run Windows Update to completion.

The snapshot to take now

Take a second one, dc-promoted, once the role is installed and working. Between those two points sits the decision that is hardest to reverse — which is the subject of the next chapter.

Two things about the virtualisation layer

Worth stating because they are easy to forget when everything above the hypervisor is what you are thinking about.

Mounted ISOs have consequences later. Leaving the Windows and virtio ISOs attached after the installation is harmless right up until something tries to enable BitLocker, which refuses to start when bootable media is present. Detach them once the drivers are installed.