Release Date:

4/11/2023

Version:

OS Build 22621.1555

For information about Windows update terminology, see the article about the types of Windows updates and the monthly quality update types. For an overview of Windows 11, version 22H2, see its update history page

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Highlights 

  • This update addresses security issues for your Windows operating system.    

Improvements

This security update includes improvements that were a part of update KB5023778 (released March 28, 2023). When you install this KB:

  • New! This update implements the new Windows Local Administrator Password Solution (LAPS) as a Windows inbox feature. For more information, see By popular demand: Windows LAPS available now!

  • This update addresses a compatibility issue. The issue occurs because of unsupported use of the registry.

If you installed earlier updates, only the new updates contained in this package will be downloaded and installed on your device.

For more information about security vulnerabilities, please refer to the Security Update Guide website and the April 2023 Security Updates.

Windows 11 servicing stack update - 22621.1550

This update makes quality improvements to the servicing stack, which is the component that installs Windows updates. Servicing stack updates (SSU) ensure that you have a robust and reliable servicing stack so that your devices can receive and install Microsoft updates.

Applies to

Symptom

Workaround

All users

After installing this or later updates, Windows devices with some third-party UI customization apps might not start up. These third-party apps might cause errors with explorer.exe that might repeat multiple times in a loop. The known affected third-party UI customization apps are ExplorerPatcher and StartAllBack. These types of apps often use unsupported methods to achieve their customization and as a result can have unintended results on your Windows device.

ExplorerPatcher and StartAllBack have released a version that lists this issue as resolved.

Note If you are using any third-party UI customization app and encounter this or any other issues, you will need to contact customer support for the developer of the app you are using.

All users

After installing this update, some apps might have intermittent issues with speech recognition, expressive input, and handwriting when using Chinese or Japanese languages. Affected apps might sometimes fail to recognize certain words or might be unable to receive any input from speech recognition or affected input types. This issue is more likely to occur when apps are using offline speech recognition.

Note for app developers This issue only affects speech recognition using Speech Recognition Grammar Specification (SRGS) in Windows.Media.SpeechRecognition. Other implementations of speech recognition are not affected.

This issue is addressed in KB5026446.

IT admins

You might have intermittent issues saving, copying, or attaching files using 32-bit apps, which are large address aware and using the CopyFile API. Windows devices are more likely to be affected by this issue when using some commercial or enterprise security software that uses extended file attributes. Microsoft Office apps, such as Microsoft Word or Microsoft Excel are only affected when using 32-bit versions and you might receive the error, "Document not saved."

This issue is unlikely to be experienced by consumers using Windows devices in their home or on non-managed commercial devices. Apps are not affected by this issue if they are 64-bit or 32-bit and NOT large address aware.

This issue is addressed in KB5027231.

How to get this update

Before installing this update

Microsoft combines the latest servicing stack update (SSU) for your operating system with the latest cumulative update (LCU). For general information about SSUs, see Servicing stack updates and Servicing Stack Updates (SSU): Frequently Asked Questions

Install this update

Release Channel

Available

Next Step

Windows Update and Microsoft Update

Yes

None. This update will be downloaded and installed automatically from Windows Update.

Windows Update for Business

Yes

None. This update will be downloaded and installed automatically from Windows Update in accordance with configured policies.

Microsoft Update Catalog

Yes

To get the standalone package for this update, go to the Microsoft Update Catalog website.

Windows Server Update Services (WSUS)

Yes

This update will automatically sync with WSUS if you configure Products and Classifications as follows:

Product: Windows 11

Classification: Security Updates

If you want to remove the LCU

To remove the LCU after installing the combined SSU and LCU package, use the DISM/Remove-Package command line option with the LCU package name as the argument. You can find the package name by using this command: DISM /online /get-packages.

Running Windows Update Standalone Installer (wusa.exe) with the /uninstall switch on the combined package will not work because the combined package contains the SSU. You cannot remove the SSU from the system after installation.

File information

For a list of the files that are provided in this update, download the file information for cumulative update 5025239

For a list of the files that are provided in the servicing stack update, download the file information for the SSU - version 22621.1550.  

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