Microsoft has confirmed that the March 12 cumulative update for Windows 10 version 1809 and version 1803 has a bug that could affect some devices booting from a Windows Deployment Service (WDS) server.
It's the fifth known issue to affect the Windows 10 version 1809 build 17763.379 that was released last Tuesday with the March Patch Tuesday security updates.
Other known issues include Internet Explorer authentication problems; audio apps like Windows Media Player and Realtek HD Audio Manager not working; a Microsoft Core XML Services 6.0 (MSXML6) bug; and a bug triggered by the security update affecting corporate apps accessed through Internet Explorer.
The fifth issue relates to WDS, a service that enterprise admins can use to centrally deploy Windows by sending preboot messages to the Preboot eXecution Environment (PXE) of local workstations.
This particular bug only affects WDS servers with Variable Windows Extension enabled and could prevent the WDS server from downloading a Windows image.
"After installing this update, there may be issues using the Preboot Execution Environment (PXE) to start a device from a Windows Deployment Services (WDS) server configured to use Variable Window Extension," Microsoft explains.
"This may cause the connection to the WDS server to terminate prematurely while downloading the image. This issue does not affect clients or devices that are not using Variable Window Extension."
Microsoft has offered three different avenues for admins to disable Variable Window Extension on a WDS server.
"Microsoft is working on a resolution and will provide an update in an upcoming release," the company notes.
Devices running the March 12 build of Windows 10 version 1803 via WDS with Variable Window Extension enabled will likely be experiencing the same problems and can use the same workarounds.