There are also of ReFS fixes that also need to be activated through overrides (e.g. see Veeam's forum regarding ReFS issues - post "Server 2025 - high CPU and RAM" in "Main > Products > Veeam Backup & Replication"). I have the following: [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Policies\Microsoft\FeatureManagement\Overrides] "593004686"=dword:00000001 "815149711"=dword:00000001 "861440142"=dword:00000001 "882258575"=dword:00000001 "1150694031"=dword:00000001 "1230538894"=dword:00000001 "1398311054"=dword:00000001 "1633192078"=dword:00000001 "1176759950"=dword:00000001 Last is the NVMe option (1176759950). Others relate to ReFS as per Veeam post.
Found the reason of this problem. It happens because of non-working Storage WMI. Which, in turn, does not work because the PE networking is not initialized. So, if the network is disabled in Unattend.xml, then Storage WMI do not work (whereas other WMI classes works Ok). And, if the network is enabled, then Storage WMI works as expected. (In Windows Server 2022 it works in both cases.)
However an updated Jan 2026 Server IoT 2025 ISO was apparently released on MSOEM yesterday and it is not often updated ISOs are put up on there.
Hi all, My Windows Server 2025 VM is stuck on the November build (26100.1742) and won’t update to the January 2026 builds. Windows Update, manual MSU installs, and DISM repairs all fail with no clear error. I checked Microsoft’s known issues, but nothing currently documented should block January updates—issues. I’ve also reviewed reported update failures seen on some Server 2025 systems, but those don’t match my symptoms. At this point, something—possibly an undocumented safeguard hold—is silently blocking upgrades. Even an in‑place upgrade using the December ISO fails: the setup dialog opens completely blank with no explanation. Last resort would be a full reinstall from ISO, but I’d appreciate guidance before going that route. Can anyone point me to a link on how to UUP generate a Windows Server 2025 2026-01 version ISO. Thanks