BUG: Installing Microsoft Windows Server 2025 fails (related to NUMA / CPU- & Memory Hotplug)

[nvanaert]

Hello everyone,

I'm experiencing issues installing Microsoft Windows Server 2025. Whenever I try to install this operating system, the installer goes up to 15% and then just shows a message: "Windows server installation has failed.", no other useful information.

Has anyone experienced this and how to resolve this issue?

What I've tried so far:
- Three different Microsoft Windows Server 2025 ISO's (all of them show the exact same problem)
- Switching from VirtIO SCSI to SATA (to make sure the VirIO drivers were not causing issues)
- Two different VirtIO driver versions
- Switching from CPU type host to x86-64-v2


I'm running Proxmox 9.1.4 on a ZFS backed store.

 

[nvanaert]

Update: I've got past the installer. It's likely a bug, related to NUMA or CPU / Memory hotplug as those are the features that I've turned off.
Update 2: Once the installation is done I can turn on NUMA and CPU / Memory Hotplug and I do not seem to be having any issues (as in the system seems to boot fine)

 

[nvanaert]

Update 2: I've tested this on 2 more Proxmox 9.1.4 hosts (which are not in a cluster) and can replicate this exact behavior, so most definitely a bug.

 

[nvanaert]

Another update: I've verified the checksums of the ISO's just to be sure and all of them matched, so there's no corrupted ISO's at all (even when uploaded from the GUI).