KB5009543 Security Update Windows 10 21H1, 20H2, & 2004

Another Patch Tuesday is here with Microsoft’s monthly security update for January 2022. As of today, a new cumulative update KB5009543 has been released for Windows 10 21H1, 20H2, and 2004 with significant changes and quality improvements. Here the build numbers increase for Windows 21H1, 20H2, and 2004 to 19042.1466, 19043.1466, and 19044.1466, respectively. New system applications updates also address a few issues.

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The update solves an issue where multiple attribute changes do not result in new Active Directory (AD) attributes being created during LDAP modification operations. Additionally, it resolves an issue with the Japanese Input Method Editors (IME) that causes text to be shown out of order, or for applications to move text cursors unexpectedly.

Patch Tuesday

Users of Windows 10 1809 receive KB5009557, a security update that increases the build number to 17763.2452. And for devices running Windows 10 1607, the build number of KB5009546 has been increased to 14393.4886.

For those who have upgraded to Windows 11, Microsoft has released KB5009566 updates which increase the build number to 22000.434. 

Here is the changelog for Windows 10 21H1, 20H2, & 2004 –

Windows 10, version 21H2 and 21H1

This quality update includes the following key changes:

  • The updates in this build are all from Windows 10, version 20H2.
  • Other issues have not been reported with this version.

Windows 10, version 20H2

The update contains quality improvements. It includes:

  • Fixes a problem that prevents multiple Active Directory (AD) attributes changes from being properly written during LDAP Modify operations.
  • This update resolves a known issue with Japanese Input Method Editors (IME). You might experience a problem where the text appears out of order or the cursor moves unexpectedly when using a Japanese IME.

Known Issues for KB5009543

1. Symptom

There may be issues installing Microsoft Edge Legacy on devices with custom offline media or custom ISO images. These devices are not automatically replaced by the updated version of Microsoft Edge. As a result, this problem may occur when you incorporate the update into a custom offline media file.


To resolve this problem, slipstream the LCU to the offline media before you slipstream the SSU in March 2021. This can be done using the SSU file found in the combined LCU and SSU package now used for Windows 10 versions 20H2 and 2004.

2. Symptom

After installing the updated version KB5003690 (June 21, 2021), some devices are unable to install new updates. It includes the July 6, 2021 update (KB5004945) and later updates. The error message you will receive will be “PSFX_E_MATCHING_BINARY_MISSING”.


Microsoft is working on a solution to this problem.

3. Symptom

Installing this update will affect your ability to connect to remote desktops in untrusted domains. At this point, you may see the message “Your credentials did not work. The credentials that were used to connect to [device name] did not work. Please enter new credentials.” and “The login attempt failed.” in red.


You can fix this problem by using Known Issue Rollback (KIR). It may take 24 hours for the resolution to be propagated automatically to non-managed devices such as personal devices.

How to get KB5009543 Update

 As part of the latest cumulative update (LCU), Microsoft includes the latest servicing stack update (SSU) for your operating system. These are the methods you can use to download KB5009543 cumulative updates.

Download KB5009543

1] Windows Update

To download the KB5009543 security update, use the following steps:

  • Right-click on Start and select Settings.
  • Select Windows Update from the left pane of the screen.
  • Now go to the right pane and click Check for Updates.

This will download and install the update automatically. When it has finished downloading, restart your computer to complete the installation.

2] Microsoft Update Catalog

If the automatic search fails to locate the pending patch, use Microsoft Update Catalog instead. Here are the steps:

  • Go to the Microsoft Update catalog page.
  • In the search field, type in KB5009543 and press Enter. It will open the available updates list.
  • Now choose your system architecture (x86, ARM64, x64) then click on the Download button.
  • Next, click the top link to begin downloading the KB5009543.
  • Once it downloads the update, right-click the “.MSU” file and then install it.

3] Windows Server Update Services (WSUS)

These are the configuration to get the update with WSUS –

  • Product: Windows 10, version 1903 and later
  • Classification: Security Updates

Release Note

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