No Boot after installing RDS on Windows Server 2025

Can confirm that as well - using host is also my preferred way.
Will wait until this problem has been fixed somewhere in the future.
 
Upgrade to v266 , v248 hangs with high usage using virtio-scsi


"host" allow nested virtualization used by Windows VBS ( or Hyper-V or WSL ) which can too slow or break boot.
Just doubled checked: There is nothing in context nested virtualization running on the VM. It's an out of the box VM, domain joined, roles installed and promoted as DC.
No WSL, no Hyper-V and also no VBS.

My PVE would in general support nested virtualization.
 
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As an additional info: Initially I tried to do an inplace upgrade which worked (somehow). The server had his DC role installed and it booted normally
 
Okay I have done that: Just installed a new standalone 2025 server: It worked, not hypervisor stuff enabled.
Joining the domain and upgrading it to DC -> BSOD.

Running dcdiag /q gave me the information that virtualbased security at phase 0 is not supported.
Original output (German)

Code:
            Erstellungszeitpunkt: 04/14/2025   06:20:13
            Ereigniszeichenfolge: Fehler beim Hypervisorstart. SVM ist entweder nicht vorhanden oder im BIOS nicht aktiviert.
         Fehler. Ereignis-ID: 0x0000007C
            Erstellungszeitpunkt: 04/14/2025   06:20:13
            Ereigniszeichenfolge: Bei der Prüfung der Richtlinie zur Aktivierung der virtualisierungsbasierten Sicherheit in Phase 0 ist ein Fehler mit dem Status Die Anforderung wird nicht unterstützt. aufgetreten.


On the other hand I have a running Windows server 2025 which acts as a file server (in place upgrade). VBS is enabled there and this works out of the box.
 
Searching the internet for similar troubles provided some useful information via Broadcoms site:

After VBS is enabled on VMware vSphere ESXi (AMD) virtual machines, the Windows Server 2025 and Windows 11 v24H2 guest operating systems boot to Automatic Repair as shown in below screenshot.
Source: https://knowledge.broadcom.com/external/article/371301/windows-server-2025-and-windows-11-v24h2.html

I downloaded the mentioned KB package and installed it on my Windows Server 2025 and set the CPU to host.
The VM booted normally and VBS is also running.

Would be great if someone else could try this and confirm if this is working.
 
What build number of your Windows Server 2025 iso ?
Because Windows Server 2025 iso GA is 26100.1742 build, released in September 2024,
which include KB5039239 (build 26100.863) released in June 2024 as monthly updates are cumulative.
 
Seems the Eval with 26100.1 (check from winver after install) build from April 2024 which missing June 2024 update.

Windows Server 2025 officiale release date is November 2024 with 26100.1742 which include update.
 
Okay but what is interesting: Even after full patching the version from April 2024 I was not able to use "host" CPU.
After installing this KB package I was.
 
I installed a 2nd 2k25 server, updated it until no further update was available and CPU type = host works.
So I guess the OP has used an ISO file which does not include the previously mentioned KB package.
 
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