Homelab #2 Windows 2022 + Autounattended on Proxmox

1. Why Windows 2022?

My machine used to run Windows 2022. After moving to Proxmox, the first lab task was… reinstalling Windows into a VM.
Goal:

• Automate installation with Autounattended.xml to skip manual config steps

2. Getting familiar with Proxmox

You should read these two posts by Thuận if you’re new:

• Getting to know the Proxmox interface
• How to create a VM in Proxmox

3. Problems during Windows install

Issue 1: UEFI won’t boot

• When creating a Windows Server 2022 VM, I selected OVMF (UEFI) by default → but the Windows ISO wouldn’t boot.
• Fix: switch to SeaBIOS → Windows boots normally.
  

Issue 2: GPT vs MBR in Autounattended

• In Autounattended.xml, there’s a step to format the disk.
• If you boot with BIOS (SeaBIOS), make sure you choose the right GPT or MBR.
• I missed that at first, so Windows couldn’t see a disk to install to.
  

Issue 3: XML syntax errors

• Autounattended is very easy to break with tiny syntax mistakes.
• I once forgot exactly one line:

  <Active>true</Active>
  

• Result: the System Reserved partition wasn’t active, so Windows wouldn’t boot.
  

4. Result

• After struggling through 8 ISO generations, the 8th one finally worked.
  
• Now just mount the ISO in Proxmox and kick back while Windows installs.
  

Summary

• BIOS mode: SeaBIOS boots Windows more easily than OVMF.
• Partition style: choose the right GPT/MBR in Autounattended.
• XML syntax: one wrong line like <Active>true</Active> and it’s broken.
• Result: one “automated” ISO → quick Windows Server 2022 install in Proxmox.