Microsoft has fixed a bug blocking some Azure Virtual Desktop (AVD) devices from downloading and installing monthly security via WSUS since early July. The issue impacted both client (Windows 10 Enterprise multi-session, version 1909) and server (Windows Server multi-session, version 1909) platforms.

Microsoft says it addressed the Azure Virtual Desktop issue in the KB5005565 cumulative update released in mid-September for devices running Windows 10, version 2004 and later.

The company did not explain on the Windows health dashboard or the associated support document why it delayed announcing the fix or why it delivers it to systems running Windows 10 1909 Cumulative updates

The first workaround requires deploying up-to-date images to all impacted devices, including all Azure Marketplace security updates.

The second approach, needed on computers where image redeployment is not an option, requires manually downloading and installing the missing security updates from the Microsoft Update Catalog.