Windows Server 2025: Fixes for Critical BSOD, Installation, and iSCSI Boot Issues

Microsoft has recently addressed critical issues affecting Windows Server 2025, particularly those leading to Blue Screen of Death (BSOD) errors and installation failures on systems with a high core count. These problems, which emerged shortly after the server's release, have now been mitigated through a series of updates and workarounds.

Understanding the Core Issue​

Windows Server 2025 introduced advanced features aimed at enhancing performance and scalability. However, systems equipped with more than 256 logical processors began experiencing significant issues:

• Installation Failures: Attempts to install or upgrade to Windows Server 2025 would often fail or hang indefinitely.
• Extended Boot Times: Servers took excessively long—sometimes over three hours—to restart or boot up.
• BSOD Errors: Frequent blue screen errors occurred during application launches, restarts, or general usage.

These issues were not consistently triggered across all high-core-count systems, making diagnosis and resolution challenging.

Microsoft's Response and Resolution​

In response to these critical issues, Microsoft released the KB5046617 update on November 12, 2024. This cumulative update addressed the problems associated with high-core-count systems by:

• Fixing Installation and Upgrade Failures: Ensuring smoother installation and upgrade processes without unexpected hangs.
• Reducing Boot Times: Optimizing startup sequences to prevent prolonged boot durations.
• Eliminating BSOD Errors: Resolving the underlying causes of blue screen errors during various operations.

Microsoft strongly recommends that all users install the latest security updates to benefit from these improvements.

Temporary Workaround for Immediate Relief​

For administrators unable to apply the KB5046617 update immediately, Microsoft provided a temporary workaround:

• Access UEFI Setup: Restart the server and enter the UEFI firmware settings.
• Adjust Core Settings: Navigate to the firmware menus to locate options for adjusting the number of cores per socket.
• Limit Logical Processors: Set the number of cores per socket to ensure the total number of logical processors does not exceed 256.
• Restart the Server: Apply the changes by restarting the server.

This workaround effectively reduces the system's logical processor count, mitigating the issues until the update can be applied.

Additional Challenges: iSCSI Boot Errors​

Beyond the high-core-count issues, Microsoft identified another critical problem affecting Windows Server 2025 systems operating in iSCSI environments. Servers booting from an iSCSI Logical Unit Number (LUN) under NDIS Poll Mode encountered "boot device inaccessible" errors during startup.
To address this, Microsoft released the KB5051987 cumulative update on February 11, 2025, which resolved the iSCSI boot error and included fixes for USB audio and camera issues that arose after the January 2025 security updates.

Implications for Enterprise Environments​

These developments underscore the complexities inherent in deploying and maintaining high-performance server environments. Organizations relying on Windows Server 2025 must remain vigilant, ensuring that systems are updated promptly to maintain stability and performance.
The proactive release of updates like KB5046617 and KB5051987 reflects Microsoft's commitment to addressing critical issues swiftly. However, the necessity for temporary workarounds highlights the importance of robust contingency planning in IT operations.

Best Practices for Administrators​

To mitigate similar issues and ensure system stability, administrators should:

• Regularly Monitor System Performance: Keep an eye on server performance metrics to detect anomalies early.
• Stay Informed on Updates: Subscribe to Microsoft's release notes and security bulletins to stay updated on patches and fixes.
• Test Updates in Staging Environments: Before deploying updates to production servers, test them in a controlled environment to identify potential conflicts.
• Implement Redundancy Measures: Ensure that critical systems have failover mechanisms to maintain operations during unexpected failures.

Conclusion​

The resolution of the BSOD and installation issues in Windows Server 2025 serves as a reminder of the challenges associated with cutting-edge technology deployments. While Microsoft's swift response has alleviated these specific problems, ongoing vigilance and proactive management are essential to navigate the complexities of modern server environments.
By adhering to best practices and staying informed about system updates, organizations can ensure that their server infrastructures remain robust, secure, and capable of supporting their operational needs.

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Source: www.bleepingcomputer.com https://www.bleepingcomputer.com/news/microsoft/microsoft-fixes-windows-server-2025-blue-screen-and-install-issues/&ved=2ahUKEwjji4yWpfeMAxWaSzABHdCUDUs4ChDF9AF6BAgJEAI&usg=AOvVaw2ztuDofpUOqEr9CKhbl5nb/