Windows App forgets how to log in with first security update of the year

January patch trips up Azure Virtual Desktop and Windows 365 authentication

Microsoft has kicked off 2026 with another faulty Windows update. This time, it is connection and authentication failures in Azure Virtual Desktop and Windows 365 related to the Windows App.

The January 2026 security update, released on January 13, is the culprit. According to Microsoft, the update can result in credential prompt failures "during Remote Desktop connections using the Windows App on Windows client devices, impacting Azure Virtual Desktop and Windows 365."

The upshot is that connecting to Windows 365 or Azure Virtual Desktop from the Windows App could be borked due to credential problems. Microsoft posted: "Investigation and debugging are ongoing, with coordination between Azure Virtual Desktop and Windows Update teams."

The problem is widespread and appears to affect every supported version of Windows, from Windows 10 Enterprise LTSC 2016, right up to Windows 11 25H2. Windows Servers 2019 to 2025 are also affected.

Other than a swift uninstall of the update (which means losing important security fixes), Microsoft's advice is to use the Remote Desktop Client to connect to Azure Virtual Desktop, or to use the Windows App web client.

Neither is an ideal solution. Microsoft said: "We are actively working on a resolution and plan to release an out-of-band (OOB) update in the coming days. Additional details will be shared as soon as they become available."

Of the suggestion to use the Remote Desktop Client, one user wrote: "Thanks Microsoft, glad we spent ages migrating everyone over to Windows App."

The Windows App is Microsoft's one-stop shop for everything Windows launched via a rebranding exercise in 2024. According to Microsoft at the time, it "serves as your secure gateway to connect to Windows across Windows 365, Azure Virtual Desktop, Remote Desktop, Remote Desktop Services, Microsoft Dev Box, and more." Until, of course, it doesn't.

Another user reported: "It throws an 'Unable to Authenticate' error every time you try to click the 'Connect' button from Windows App. It instantly fails with the 'Unable to Authenticate' error."

According to reports, Microsoft has made a Known Issue Rollback available to reverse whatever is causing the Windows App credential issues. However, the company has yet to publicize this on its Release Health dashboard.

If Microsoft's resolution for 2026 was to "stop shipping borked software," it appears to have made it as far as the first security update of the year. ®