Microsoft fixes Windows Server 2025 blue screen, install issues

Microsoft has fixed several known issues that caused Blue Screen of Death (BSOD) and installation issues on Windows Server 2025 systems with a high core count.

As Redmond said when it acknowledged this known issue in October, impacted devices may experience a wide range of symptoms, including Windows Server 2025 installation or upgrading processes failing or hanging, and server start-up taking as much as three hours or more in some cases.

Affected systems might also get blue screen errors when launching, restarting, or attempting to run apps. However, these issues are not consistently triggered on impacted servers.

“Servers which have a high number of logical processors might experience issues running Windows Server 2025. This is presently observed on servers which have more than 256 logical processors,” the company said.

IT admins who want to find out if these known issues impact their Windows Server 2025 systems are advised to check if they show as having over 256 logical processors on the Performance tab in the Windows Task Manager.

In an update to the initial Windows release health entry, Microsoft says these issues have been addressed in updates released since the KB5046617 cumulative update issued as part of the November Patch Tuesday.

“We recommend you install the latest security update for your device as it contains important improvements and issue resolutions, including this one,” Redmond added.

Admins who can’t immediately install updates released since November can still work around these issues by limiting the number of logical processors on affected devices to 256 or under using these instructions:

1. Restart your server and enter the UEFI Setup. Navigate through the firmware menus, which may vary by manufacturer.
2. Locate any option that allows you to adjust the number of cores per socket.
3. Set the number of cores per socket to a value that ensures the total number of logical processors is 256 or fewer. Important: The total number of logical processors is calculated by first multiplying the number of sockets by the number of cores per socket and then multiplying that result by the number of logical processors per core.
4. Restart the server.

Earlier this month, Microsoft warned that some Windows Server 2025 domain controllers (DCs) might become inaccessible after being restarted, causing services and apps to fail.

The company also said that some Windows users might be unable to log into their accounts using Windows Hello after installing the April 2025 security updates on client (Windows 11 24H2) and server (Windows Server 2025) systems.

Microsoft also fixed a bug that caused authentication issues when Credential Guard was enabled on systems using the Kerberos PKINIT pre-auth security protocol, and it introduced a new Windows 11 24H2 safeguard hold for systems with SenseShield Technology’s sprotect.sys driver (used by security or enterprise software) because of incompatibility issues triggering blue or black screen of death (BSOD) errors.