Microsoft has taken significant steps to address a series of challenges affecting Windows Server 2025, particularly for systems equipped with a high core count. The company previously acknowledged these issues in October, highlighting that devices with more than 256 logical processors could experience a variety of symptoms, including installation failures, prolonged server start-up times, and sporadic blue screen errors during app launches or restarts.
Resolution and Recommendations
In an update to its Windows release health entry, Microsoft confirmed that these issues have been resolved through updates released since the KB5046617 cumulative update, which was part of November’s Patch Tuesday. The company strongly encourages IT administrators to install the latest security updates, as they encompass essential improvements and fixes, including those related to the aforementioned problems.
For administrators who are unable to implement these updates immediately, a temporary workaround is available. By limiting the number of logical processors on affected devices to 256 or fewer, they can mitigate the impact of these issues. The following steps outline how to adjust the processor settings:
- Restart the server and access the UEFI Setup. The navigation through firmware menus may differ based on the manufacturer.
- Identify any option that allows for the adjustment of cores per socket.
- Set the number of cores per socket to ensure the total number of logical processors remains at 256 or fewer. It is important to note that the total is calculated by multiplying the number of sockets by the number of cores per socket, and then by the number of logical processors per core.
- Restart the server to apply the changes.
Earlier this month, Microsoft also issued a warning regarding potential accessibility issues with Windows Server 2025 domain controllers (DCs) post-restart, which could lead to service and application failures. Additionally, some users have reported difficulties logging into their accounts via Windows Hello after installing the April 2025 security updates on both client (Windows 11 24H2) and server systems.
Moreover, Microsoft has rectified a bug that caused authentication problems when Credential Guard was enabled on systems utilizing the Kerberos PKINIT pre-auth security protocol. The company has also introduced a new safeguard hold for Windows 11 24H2 on systems with the SenseShield Technology’s sprotect.sys driver, which is associated with security or enterprise software, due to compatibility issues that resulted in blue or black screen errors.
