KB4550939 – Windows 10 1703 reaches the End of Service for all Editions

Windows 10 version 1703 reaches the end of services for all Editions after receiving the cumulative update – KB4550939. Microsoft recommends you to upgrade the existing OS to the latest version of Windows 10 so as to continue getting the security and quality patches. This Tuesday patch updates the Windows 10 1703 to Build 15063.2346. 

KB4550939 includes quality improvements for certain applications like Windows Kernel, Microsoft Graphics Component, Windows Media, and others. The company also works on the issue that causes a memory leak in the LsaIso.exe process. In order to get the latest patch list, visit Windows 10 cumulative Catalog.


Fixes and Improvements on KB4550939

The key changes on this cumulative update are as follows –

  • The company works on an issue that causes a memory leak in the LsaIso.exe process. It generally used to occur when the server is under a heavy authentication load and Credential Guard is enabled. 
  • Microsoft team tries to fix the issue associated with running klist.exe. Because of this, lsass.exe stops working and generates an access violation error (0xC0000005). 
  • The developer team tries to rectify an issue with merging Windows Defender Application Control policies. It sometimes makes a duplicate rule ID error and causes the Merge-CIPolicy PowerShell command to fail.
  • The team provides security updates to the followings:
Microsoft Scripting Engine, Windows Kernel, Windows App Platform, and Frameworks, 
Microsoft Graphics Component, Windows Media, Windows Management, Windows Fundamentals,
Windows Core Networking, Windows Update Stack, and the Microsoft JET Database Engine.

KB4550939 – Known Issues

Symptoms –

With this Tuesday patch update, the devices on a domain might not be able to install apps published using a Group Policy Object. Also, this problem only affects app installations that use .msi files. However, it does not affect any other installation methods, like – from the Microsoft Store.

Workaround –

In order to reduce this issue, you need to manually install the app on the device. Microsoft is working on a resolution. They will provide an update in an upcoming release.

How to download and apply this update

At first, download and apply the latest servicing stack i.e. KB4550992 on your PC so as to make the upgrade process smooth and effective. There are currently three different ways to update your Windows 10 v 1703 to the latest cumulative update. These are –

  1. Windows Update – You will receive a notification regarding KB4550939 on your PC. If prompted, download and apply the same.
  2. Update Catalog – Download the Standalone package and install it on your computer. 
  3. Windows Server Update Services – Just configure Product as “Windows 10” and Classification to “Security Updates”, and your system will auto-sync with the WSUS. 

Release Note