Microsoft Cloud PC access blocked by recent Windows update and a fix is planned

A January Windows security update (KB5074109) caused credential prompt failures that prevented some users from signing into Microsoft 365 Cloud PCs; Microsoft says teams are working on an out-of-band update and lists web and Remote Desktop clients as temporary alternatives.

Some users began reporting sign-in failures and intermittent access to Microsoft 365 Cloud PCs on 13 January. Microsoft attributed the problem to the January Windows security update (OS Build 26100.7623, KB5074109). The company said credential prompt failures affected Remote Desktop connections for Azure Virtual Desktop and Windows 365. Microsoft teams are working together on a fix. Known details: - Microsoft reported that credential prompt failures occurred after the January 2026 security update (KB5074109) and affected Remote Desktop connections. - Affected clients include Windows 11 25H2, 24H2 and 23H2; Windows 10 22H2 and 21H2; and Windows 10 Enterprise LTSC 2019 and 2016. - Microsoft noted a temporary alternative of using the Windows App Web Client (windows.cloud.microsoft) or the Remote Desktop client to access Azure Virtual Desktop, as reported by the company. - Microsoft said it plans to release an out-of-band (OOB) update in the coming days to resolve the issue. Summary: Some users experienced blocked access to Microsoft 365 Cloud PCs after the January update, which Microsoft has linked to a specific OS build. Microsoft reports a temporary workaround is available and that an out-of-band update is planned in the coming days.