Microsoft resolves critical issues in Windows Server 2025 update

Microsoft has released updates to resolve several critical issues in Windows Server 2025, that were impacting devices with a high core count, including failures in installation, upgrades, and Blue Screen of Death (BSOD) occurrences. The glitches affected systems with 256 or more logical processors.

On those affected systems, the installation or upgrade process for Windows Server 2025 could fail or become unresponsive. Starting or restarting the server could take an excessive amount of time, potentially more than three hours. Additionally, a BSOD error might appear when the system is started, restarted, or when an application is launched.

Redmond outlined these issues on its Windows release health dashboard, clarifying that not all affected devices experienced these problems consistently. To verify if a system is impacted, the company advised administrators to open the Windows Task Manager by pressing CTRL+SHIFT+ESC and check the Performance tab. Administrators can then confirm whether the device displays more than 256 logical processors.

The company announced that the problems have been resolved with updates released on 12 November 2024 (KB5046617) and later. Microsoft also urged users to apply the latest security updates to receive the necessary fixes and performance enhancements. However, for systems unable to implement the KB5046617 update immediately, Redmond provided a temporary workaround. Administrators can limit the number of logical processors to below 256.

To apply the workaround, restart the server and enter the UEFI Setup. Once in the setup, navigate through the firmware menus, which may vary depending on the manufacturer. Look for an option that allows adjustment of the number of cores per socket.

Set this value so that the total number of logical processors is 256 or fewer. To calculate this total, multiply the number of sockets by the number of cores per socket, then multiply that result by the number of logical processors per core. Finally, restart the server to apply the changes.

“We recommend you install the latest security update for your device as it contains important improvements and issue resolutions, including this one. If you install an update released November 12, 2024 (KB5046617) or later, you do not need to use a workaround for this issue,” stated the company.

Windows Server 2025 issues

Furthermore, Microsoft is currently investigating a separate issue affecting Windows Server 2025 devices operating in iSCSI environments, where some servers have encountered “boot device inaccessible” errors, leading to boot failures.

Windows Server 2025, which recently launched as Microsoft’s latest long-term servicing channel (LTSC) release, is intended for high-performance server environments. A 180-day free trial for Windows Server 2025 is available through the Microsoft Evaluation Center, allowing users to explore the new capabilities.

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