Introduction

In February 2025, Microsoft released security update KB5051987 for Windows Server 2025, aiming to enhance system security. 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.

Emergence of the RDP Freezing Issue

Following the deployment of KB5051987 on February 11, 2025, reports surfaced about RDP sessions freezing on Windows Server 2025 systems. Users experienced unresponsive sessions, necessitating frequent disconnections and reconnections. Microsoft acknowledged the problem, stating that the issue caused mouse and keyboard inputs to become unresponsive within the session, requiring users to disconnect and reconnect. (learn.microsoft.com)

Technical Analysis of the Problem

The freezing issue appears to stem from how the KB5051987 update interacts with the RDP infrastructure in Windows Server 2025. Specifically, the update seems to disrupt input processing within RDP sessions, leading to unresponsive mouse and keyboard inputs. This disruption suggests potential conflicts between the update's security enhancements and the server's remote session management components.

Broader Implications and Similar Incidents

This incident is not isolated. A similar issue affected Windows 11 version 24H2, where UDP-based RDP sessions disconnected after 65 seconds when connecting to Windows Server 2016 or earlier. Microsoft addressed this problem with the March 27, 2025, update (KB5053656), recommending users install the latest update to resolve the issue. (bleepingcomputer.com)

The recurrence of such issues highlights the delicate balance between implementing security updates and maintaining system stability. It underscores the need for thorough testing and validation of updates, especially in enterprise environments where remote access is critical.

Impact on Enterprise Operations

For organizations relying on Windows Server 2025, the RDP freezing issue poses significant challenges:

  • Operational Disruptions: Administrators face delays in performing essential tasks due to unresponsive remote sessions.
  • Increased Support Overhead: IT departments may experience a surge in support requests related to RDP connectivity issues.
  • Security Concerns: Delays in applying security patches or performing system maintenance can expose systems to vulnerabilities.

Mitigation Strategies

While awaiting an official fix from Microsoft, administrators can consider the following interim measures:

  1. Uninstall Problematic Updates: If the issue began after applying KB5051987, consider uninstalling the update temporarily.
  2. Configure TCP-Only RDP: Adjust Group Policy settings to use only the TCP protocol for RDP connections, which has been reported to alleviate freezing issues. (help.trugrid.com)
  3. Optimize RDP Settings: Modify RDP client settings, such as setting the experience level to "High-Speed Broadband," to improve stability.
  4. Monitor Official Communications: Stay updated with Microsoft's advisories for information on patches or workarounds.

Microsoft's Response and Resolution

Microsoft acknowledged the issue and worked towards a resolution. The problem was addressed in the April 2025 cumulative update (KB5055523), released on April 8, 2025. This update resolved the RDP freezing issue on Windows Server 2025 devices. Administrators are advised to install the latest updates to ensure system stability and security. (learn.microsoft.com)

Conclusion

The RDP freezing issue introduced by update KB5051987 in Windows Server 2025 serves as a critical reminder of the challenges inherent in system updates. Organizations must remain vigilant, implementing interim solutions to maintain operational continuity while awaiting official fixes. Engaging with the broader IT community and staying informed through official channels are essential strategies for navigating such disruptions effectively.