Windows 10 Windows 10 Cumulative Update KB4556799: Everything You Need to Know


Level 32
Nov 10, 2017
Microsoft has shipped new Windows 10 cumulative updates as part of the May 2020 Patch Tuesday cycle, including for Windows 10 version 1903 and 1909.

The two get the same cumulative update, as they share most of the code, so the changelog is exactly the same for both versions of Windows 10.

“Windows 10, versions 1903 and 1909 share a common core operating system and an identical set of system files. As a result, the new features in Windows 10, version 1909 were included in the recent monthly quality update for Windows 10, version 1903 (released October 8, 2019), but are currently in a dormant state. These new features will remain dormant until they are turned on using an enablement package, which is a small, quick-to-install “master switch” that simply activates the Windows 10, version 1909 features,” Microsoft explains.

First and foremost, the cumulative update for Windows 10 version 1903 and 1909 is KB4556799. It increases the OS build number as it follows:
  • Windows 10 version 1903: build number 18362.836
  • Windows 10 version 1909: build number 18363.836
What’s important to know is that these cumulative updates land on a Patch Tuesday, so the focus is first and foremost on security fixes supposed to resolve vulnerabilities in the operating system.

As a result, several Windows 10 apps and components are getting updates with these cumulative updates, including WSL, Microsoft Edge, Windows Media, the Windows Update Stack, and others.

There are security improvements for Microsoft Office, when using input devices like mice, keyboards, and pens, and when using Microsoft Xbox. Also, Microsoft says it has included updates for storing and managing files, as well as for verifying usernames and passwords.

A summary of the changes included in this update is below:
  • Updates to improve security when using Internet Explorer and Microsoft Edge.
  • Updates to improve security when using input devices such as a mouse, keyboard, or stylus.
  • Updates for verifying usernames and passwords.
  • Updates to improve security when using Microsoft Xbox.
  • Updates to improve security when Windows performs basic operations.
  • Updates for storing and managing files.
  • Updates to improve security when using Microsoft Office products.
As far as the typical Patch Tuesday fixes are concerned, Microsoft lists the following improvements:

“Security updates to Internet Explorer, the Microsoft Scripting Engine, Windows App Platform and Frameworks, Microsoft Graphics Component, Windows Input and Composition, Windows Media, Windows Shell, Microsoft Xbox, Microsoft Edge, Windows Fundamentals, Windows Cryptography, Windows Authentication, Windows Kernel, Windows Linux, Windows Update Stack, Windows Network Security and Containers, Windows Active Directory, Windows Storage and Filesystems, and the Microsoft JET Database Engine.”

The good news is that there are no known issues in this update. As many know already, installing cumulative updates in Windows 10 has been quite a challenge, as these often failed to install or caused other issues like broken apps, network access problems, and other errors.

But even if Microsoft says there are no known issues, this doesn’t mean everything is running flawlessly. At the time of writing this article, however, we aren’t aware of any problems encountered with the new cumulative update.

Windows 10 cumulative update KB4556799 is available through the standard distribution channels, like Windows Update and Microsoft Update for automatic rollout, the Microsoft Update Catalog for manual installation, and the Windows Server Update Services (WSUS) for enterprise deployment.

As usual, installing this cumulative update on Windows 10 version 1903 and 1909 requires a computer reboot, so users need to save their work before beginning the patching process. Creating a system restore point is also recommended to be prepared in case something goes wrong.



Level 18
Malware Tester
Sep 10, 2015
I received KB4556803 today, yep I'm using Windows 2004 since march 12th


Edit: I'm not an insider, just installed the converted ESD from techbench.
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Level 57
Content Creator
Oct 9, 2016
just installed my update no issues to report, When is the May 2020 update due to be released?
Looks like 28th this month

You always grab the latest 2004 ESD from TechBench by WZT (v4.1.1), convert it to an ISO FAQ - TechBench by WZT (v4.1.1) and do a clean install
The version posted there now looks like a old version. The latest version is 19041.264.. Not sure will be released in time.