How to Fix RDP Freezing After Windows Server 2025 KB5051987 Update

In February 2025, Microsoft released security update KB5051987 for Windows Server 2025, aiming to bolster system defenses. However, this update inadvertently introduced a critical issue: Remote Desktop Protocol (RDP) sessions began freezing shortly after connection, rendering mouse and keyboard inputs unresponsive. Administrators found themselves repeatedly disconnecting and reconnecting to regain control, significantly disrupting remote management tasks.

The Emergence of the RDP Freeze Issue​

Following the installation of KB5051987 on February 11, 2025, reports surfaced of RDP sessions freezing almost immediately after users logged in. This problem was not isolated; similar issues were observed in Windows 11 version 24H2, where UDP-based RDP sessions disconnected after 65 seconds when connecting to Windows Server 2016 or earlier. Microsoft addressed the Windows 11 issue with the March 27, 2025 update (KB5053656), but a fix for Windows Server 2025 remained pending.

Technical Analysis of the Freeze​

The freezing issue appears to stem from disruptions in input processing within RDP sessions post-update. Specifically, the update may interfere with the session's ability to handle keyboard and mouse inputs, leading to unresponsive sessions. This suggests potential misconfigurations in protocol handling or deeper interactions between updated security modules and remote session management components.

Mitigation Strategies​

While awaiting an official fix from Microsoft, administrators have explored several workarounds to mitigate the impact:

• Uninstalling KB5051987: Some administrators reported that removing the problematic update restored RDP functionality. However, this approach leaves systems without the security enhancements provided by the update.
• Disabling UDP for RDP: Configuring RDP to use only the TCP protocol has been effective in some cases. This can be achieved by enabling the "Select RDP transport protocols" policy and setting it to "Use only TCP" in the Group Policy Editor.
• Adjusting Network Detection Settings: Enabling the "Select network detection on the server" policy and setting the "Select Network Detect Level" to "Use both Connect Time Detect and Continuous Network Detect" has helped stabilize RDP sessions for some users.
• Disabling Remote Desktop Wallpaper: Some users found that disabling the display of desktop wallpapers during RDP sessions improved stability. This can be configured by enabling the "Force removal of Remote Desktop wallpapers" policy in the Group Policy Editor.

Broader Implications and Best Practices​

This incident underscores the delicate balance between implementing security updates and maintaining system stability. It highlights the importance of rigorous pre-deployment testing, especially for critical systems, and the need for robust rollback procedures to minimize downtime when issues arise. Transparent communication from vendors is also crucial to ensure that security updates do not compromise system functionality.

Conclusion​

The RDP freezing issue following the KB5051987 update serves as a reminder of the complexities involved in patch management. Administrators are advised to stay informed through official advisories and community forums, implement interim solutions as needed, and await a comprehensive fix from Microsoft to fully resolve the issue.

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Source: www.theregister.com Windows Server 2025 freezing after February patch