Overview

Microsoft's Windows Server 2025 has recently been affected by a significant technical issue following the release of the February 2025 security update KB5051987. This update, intended to improve system security, inadvertently caused Remote Desktop Protocol (RDP) sessions to freeze shortly after connection, rendering mouse and keyboard inputs unresponsive. This critical problem forced users and administrators into repeatedly disconnecting and reconnecting sessions, severely disrupting remote management workflows and enterprise operations.

Background and Technical Context

The February 11, 2025 security update KB5051987 was rolled out to enhance the security posture of Windows Server 2025 systems. However, after its deployment, many users reported that RDP sessions would initially connect but freeze moments later, causing complete lock-up of input devices such as the mouse and keyboard within the remote session window.

This issue is distinct in severity compared to an earlier related problem on Windows 11 version 24H2, where UDP-based RDP sessions disconnected after approximately 65 seconds rather than freezing outright. The Windows 11 freezing was addressed earlier with update KB5052093 in late February 2025, and the disconnect issue was mitigated on March 27, 2025, with KB5053656.

The Windows Server 2025 freezing bug is thought to stem from conflicts introduced by security hardening measures in KB5051987. These changes likely disrupted Remote Desktop session management protocols and the handling of input streams, causing the session to become unresponsive to user input after connection establishment. Although Microsoft has not disclosed all technical specifics, analysis suggests the issue is deep within how updated components interact with the RDP infrastructure and potentially legacy network or driver modules.

Impact and Implications

Remote Desktop is a foundational tool in modern IT administration, enabling remote management of servers and network devices without physical presence. The freezing issue severely impacted enterprise environments as it:

  • Reduced productivity by forcing administrators to repeatedly disconnect and reconnect.
  • Increased administrative overhead and support requests related to failed remote sessions.
  • Raised concerns on update reliability and stability in mission-critical systems.
  • Delayed critical server maintenance, monitoring, and security patching activities.

Given the centrality of RDP in remote work and system administration, this issue posed operational and security risks that necessitated urgent remediation.

Workarounds and Interim Solutions

While awaiting an official fix, administrators explored various workarounds, including:

  1. Adjusting Group Policy Settings: Enabling network detection policies to optimize session stability.
  • Navigate to Group Policy Editor
  • Under Remote Desktop Services > Remote Desktop Session Host > Connections
  • Enable "Select network detection on the server" and configure detection levels
  1. Disabling UDP for RDP: Forcing RDP to use TCP only to avoid UDP-related session freezes.
  • In Group Policy Editor, under Remote Desktop Services settings
  • Enable "Select RDP transport protocols" and set to "Use only TCP"
  1. Uninstalling KB5051987: Rolling back the problematic update to regain remote session usability, though this reduces security protections.

Administrators balanced these mitigations against potential security exposures and the practicality of applying them pending a permanent fix.

Microsoft’s Response and Resolution

Microsoft publicly acknowledged the issue through their Windows Release Health Dashboard, confirming that after installing KB5051987, Windows Server 2025 devices could experience RDP input freezes post connection.

After a protracted period of community reports and investigation, Microsoft released a critical fix with update KB5055523 in late April 2025. This patch addressed the freezing issue specifically on Windows Server 2025, restoring reliable remote session responsiveness and resolving mouse and keyboard input lock-ups.

This fix was distinct from the earlier Windows 11 update patches and the emergency Known Issue Rollback (KIR) deployments that managed other concurrent system issues such as Blue Screen of Death errors.

Broader Context and Lessons Learned

The Remote Desktop freezing issue highlights the challenges and complexities in deploying security patches to complex server operating systems. It exemplifies the delicate trade-off between improving security and maintaining system stability. Frequent patch cycles raise risks of regressions, emphasizing the need for rigorous testing, phased rollouts, and swift communication with enterprise users.

IT teams and administrators benefit from proactive monitoring of official advisories, participation in community forums, and preparedness to apply interim mitigations in times of patch-induced disruptions.

Summary

  • Windows Server 2025 February 2025 security update KB5051987 introduced a critical Remote Desktop freeze issue.
  • The freeze causes mouse and keyboard inputs to become unresponsive soon after session connection.
  • The issue disrupts enterprise remote management, forcing repeated session reconnections.
  • Interim workarounds include group policy adjustments, disabling UDP, and uninstalling the patch.
  • Microsoft released a fix with update KB5055523 in late April 2025.
  • The incident underscores patch management challenges balancing security and operational stability.