Windows App forgets how to log in with first security update of the year
Summary
Microsoft’s January 2026 security update (released 13 January) has caused credential prompt and authentication failures in the Windows App when connecting to Azure Virtual Desktop and Windows 365. Affected systems include a wide range of client and server releases — from Windows 10 Enterprise LTSC 2016 through Windows 11 25H2 and Windows Server 2019 up to 2025.
The company says investigation is ongoing and plans to release an out-of-band (OOB) fix in the coming days. In the meantime Microsoft recommends uninstalling the update (which sacrifices the security fixes) or using the Remote Desktop Client or the Windows App web client as workarounds. Some customers report an immediate ‘Unable to Authenticate’ error when attempting to connect via the Windows App. A Known Issue Rollback appears to be available to reverse the change, though Microsoft has not prominently listed it on the Release Health dashboard.
Key Points
- The January 2026 security update is causing credential prompt failures in the Windows App for Azure Virtual Desktop and Windows 365.
- Issue affects many supported Windows client and server versions, including Windows 10 Enterprise LTSC 2016 through Windows 11 25H2 and Windows Server 2019–2025.
- Reported symptom: instant ‘Unable to Authenticate’ error when clicking Connect in the Windows App.
- Microsoft recommends uninstalling the update or using the Remote Desktop Client or web client as temporary workarounds.
- Microsoft is investigating and intends to issue an out-of-band update; a Known Issue Rollback may be available but is not clearly advertised on Release Health.
Context and Relevance
This matters if your organisation uses Azure Virtual Desktop, Windows 365 or relies on the Windows App as the gateway for remote sessions. The bug impacts connectivity rather than exposing data, but it can halt remote access for many users and complicate patch management decisions (leave the update installed and risk broken logins, or remove it and lose security fixes).
It also highlights ongoing risks around large-scale monthly patches: even widely promoted, consolidated apps like the Windows App (rebranded in 2024 as a one-stop Windows gateway) can become a single point of failure when updates go wrong. IT teams will want to monitor Microsoft’s Release Health and be ready to apply the OOB fix when released.
Why should I read this?
Quick and blunt: if you manage Windows, Azure Virtual Desktop or Windows 365, this could stop people getting any work done. It tells you what breaks, which versions are hit, the temporary workarounds, and where Microsoft is up to on a fix — so you don’t have to waste time digging through forums yourself.