Applies To.NET

Revised July 7, 2025: Updated 'How to get this update' section. 

Revised July 10, 2025 : Updated 'How to get this update' section.  A known issue section has been added.

Revised July 14, 2025 : Updated the Resolution in the Known Issue section.

IMPORTANT

This update was originally released in the Security and Quality Rollup that’s dated April 22, 2025.  This update is included in the Security and Quality Rollup that’s dated July 8, 2025.  There is no change to this update with this release on July 8, 2025.  If you have previously installed this update no action is needed.

Release Date:July 8, 2025

Version:.NET Framework 3.5 and 4.8.1

The April 22, 2025 update for Windows 11, version 22H2 and Windows 11, version 23H2 includes security and cumulative reliability improvements in .NET Framework 3.5 and 4.8.1. We recommend that you apply this update as part of your regular maintenance routines. Before you install this update, see the Prerequisites and Restart requirement sections.

Summary

Security Improvements

There are no new security improvements in this release. This update is cumulative and contains all previously released security improvements.

Quality and Reliability Improvements

.NET Libraries

- Addresses an issue with concurrency in TypeDescriptor.GetConverter()issue in TypeDescriptor GetProperties() and GetConverter().

.NET Runtime

- Addresses an issue where interactions between .NET Framework DLL loads and OS code integrity enforcement policy trigger error reporting dialog boxes.

Known issues in this update

Symptom

The Windows 11, version 22H2 package KB5056580 was not available on Windows Server Update Services (WSUS) or Microsoft Update Catalog.  It was still available on Windows Update and Microsoft Update.

Workaround

To work around the issue, the update can be installed through Windows Update and Microsoft Update.  See the How to get this update section below for instructions.

Resolution

The Windows 11, version 22H2 package KB5056580 was published on Windows Server Update Service (WSUS) and Microsoft Update Catalog on July 14th, 2025.

Note: The Windows 11, version 23H2 package KB5056580 was available on all release channels.

How to get this update

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.

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, version 22H2 and Windows 11, version 23H2

Classification: Updates

File information

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

Prerequisites

To apply this update, you must have .NET Framework 3.5 or 4.8.1 installed.

Restart requirement

You must restart the computer after you apply this update if any affected files are being used. We recommend that you exit all .NET Framework-based applications before you apply this update.

How to obtain help and support for this update

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