Windows Update Blocks Cloud PC Access
▼ Summary
– A recent Windows update is blocking Microsoft 365 Cloud PC access, causing sign-in failures and connection issues for enterprise customers.
– Microsoft’s automated monitoring detected the problem, and engineers identified a recent Windows 365 security update as the cause.
– The company is analyzing the update to determine a mitigation plan while offering temporary workarounds via web or Remote Desktop clients.
– The incident, tracked as WP1217671, is flagged as causing service degradation and affects multiple Windows and Server versions.
– A related known issue is acknowledged with the January 2026 KB5074109 security update, causing authentication errors for Remote Desktop connections.
A recent Windows update has created significant access issues for users of Microsoft’s cloud-based desktop service. Microsoft has confirmed that a specific update is preventing customers from signing into their Microsoft 365 Cloud PC sessions, disrupting a key enterprise tool. The Windows 365 service, which streams a full Windows experience from the cloud via Azure Virtual Desktop, became inaccessible for many starting Tuesday evening UTC. Users reported sign-in failures and intermittent problems connecting to their virtual desktops.
Microsoft’s automated monitoring systems flagged the incident after detecting a sharp rise in failed connection attempts. The company immediately launched an investigation, analyzing service telemetry and recent updates to pinpoint the root cause. Engineers determined that a Windows 365 update designed to enhance security functionality is responsible for the widespread connection failures. This problematic update is now under intense scrutiny to develop an effective mitigation strategy.
While the company works on a permanent resolution, it has provided two temporary workarounds for affected users. One method involves accessing the Cloud PC through the Windows App Web Client at the official windows.cloud.microsoft address. The alternative is to use the Remote Desktop client for Windows to establish a direct connection to Azure Virtual Desktop. These steps are intended to restore access while a fix is engineered.
Microsoft has classified this situation as a service degradation incident, a term reserved for critical issues with substantial user impact. Although the exact number of affected users and specific regions have not been disclosed, the problem is clearly widespread. In a related advisory on its release health dashboard, Microsoft acknowledged a known issue stemming from a January 2026 Windows security update, KB5074109. This update triggers authentication errors and connection failures during Remote Desktop sessions to both Azure Virtual Desktop and Windows 365.
The platforms impacted by this problematic update include Windows 11 versions 25H2 and 24H2, as well as Windows Server 2025, Server 2022, and Server 2019. The incident underscores the complex challenges of managing cloud infrastructure and security updates at scale, where a single change can inadvertently block access for enterprise users relying on these virtual environments for their daily work.
(Source: Bleeping Computer)
