Heads up: Microsoft’s January 2026 cumulative update KB5074109 is causing credential prompt failures in the Windows App when connecting to Azure Virtual Desktop (AVD) and Windows 365 Cloud PCs. Users see repeated prompts or can’t complete sign-in on affected Windows builds. Microsoft has confirmed the issue and says an out-of-band (OOB) fix is coming.
This month’s update is otherwise a routine Patch Tuesday (battery/NPU and security fixes), but if your team relies on AVD, this bug is disruptive.
Who’s impacted?
- Clients: Windows 11 24H2/25H2 (build 26100.7623) and other supported Windows versions where the Windows App is used to connect.
- Symptom: The Windows App fails at the credential prompt or loops on sign-in. Data is not affected—this is an auth/connectivity regression.
- Mac Windows App is unaffected.
IT admin playbook (Intune/Autopatch)
A) Pause deployment
Windows Update rings (Intune): Increase Quality update deferral or use Pause for 7 days on rings that haven’t received KB5074109 yet.
B) Targeted rollback
Uninstall KB5074109.
https://windowsreport.com/windows-update-kb5074109-breaks-azure-virtual-desktop-connections
https://windowsforum.com/threads/kb5074109-regression-breaks-avd-auth-kir-and-workarounds.397039
