KB5074975 (OS Build 17763.8148) Out-of-Band Update for Windows 10 LTSC 2019 and Server 2019

Summary

This is an out-of-band update for Windows 10 Enterprise LTSC 2019 and Windows Server 2019, producing OS Build 17763.8148. Released on December 18, 2025, it targets a specific regression in Message Queuing (MSMQ) introduced by the December 9, 2025 updates. It is not a scheduled monthly release. See Microsoft Support for the official page.

Improvements and fixes

• MSMQ regression fix: Resolves a problem introduced by the Windows updates released on December 9, 2025, in which Message Queuing (MSMQ) functionality broke on affected systems. The fix also covers clustered MSMQ environments running under load. Symptoms of the original regression included message queues going inactive, errors about insufficient resources, applications failing to write to message queues, errors stating a message cannot be created, and errors about insufficient disk space or memory. This issue primarily affected enterprise and managed IT environments; users on Windows Home or Pro personal devices were very unlikely to encounter it.

Known issues

Microsoft lists no known issues for this update at the time of writing.

How to get this update

Prerequisite: Before installing this cumulative update, you must have the August 10, 2021 servicing stack update (SSU) - KB5005112 - already installed.

This update is available through the following channels:

• Windows Update / Windows Update for Business - available; see the Update Catalog for the standalone package.
• Microsoft Update Catalog - the standalone package can be downloaded directly from the Microsoft Update Catalog website.
• Server Update Services (WSUS) - available; the update is obtainable from the Update Catalog.

Bundled SSU: This release also bundles the servicing stack update KB5070248 (version 17763.8020). Microsoft now ships the latest SSU together with the cumulative update to improve update-installation reliability.

Removing the update: To uninstall only the cumulative update portion after installing the combined SSU and LCU package, use the DISM /Remove-Package command with the LCU package name as the argument. You can find the package name by running DISM /online /get-packages. Running wusa.exe /uninstall against the combined package will not work because the package contains the SSU, and the SSU cannot be removed from the system after installation.

Frequently asked questions

Who is most affected by the MSMQ issue this update fixes?

This fix primarily targets enterprise and managed IT environments that use Message Queuing (MSMQ), including clustered MSMQ setups. Microsoft states that users on Windows Home or Pro personal devices are very unlikely to have experienced the original problem introduced by the December 9, 2025 updates.

Do I need to uninstall the December 9 update before applying KB5074975?

No. The page states that if you have already installed earlier updates, only the new content in this package will be downloaded and installed on your device. You do not need to roll back KB5071544 before deploying this out-of-band release.

What is the servicing stack update included in this package?

The bundled SSU is KB5070248, version 17763.8020. Microsoft combines the latest SSU with the cumulative update to improve reliability of the update process. Note that once installed, the SSU component cannot be removed from the system.

When do Windows Server 2019 and Windows 10 Enterprise LTSC 2019 reach end of support?

Microsoft states that both Windows Server 2019 and Windows 10 Enterprise LTSC 2019 reach end of support on January 9, 2029, after which Microsoft will no longer provide free software updates, technical assistance, or security fixes for those products.