The Update BureauKB5056577: Cumulative update for .NET Framework, versions 3.5 and 4.8, on Windows 10 21H2/22H2, July 2025. TypeDescriptor concurrency and .NET error dialogs addressed
In short
The update addresses two .NET reliability issues: concurrency in TypeDescriptor calls and error dialogs during DLL loads. The July 8 release is unchanged from April 22; if you already installed it, no action is needed.
Does it affect you? Applies to: Windows 10 version 21H2 and 22H2 devices with .NET Framework 3.5 or 4.8 installed, including Windows 10 Enterprise LTSC 2021.
What changes
Fixes 2 changes
.NET Libraries
-
A concurrency issue involving .NET type properties and converters is addressed.1
Addresses a concurrency issue involving
TypeDescriptor.GetProperties()andTypeDescriptor.GetConverter().
.NET Runtime
- Error-reporting dialog boxes caused by interactions between .NET Framework DLL loads and OS code integrity enforcement are addressed.2
Technical details
Data sheet · Security · Downloads · Components Click to collapse or expand
Data sheet
- Released
- 2025-07-08
- Classification
- Updates
- Type
- Cumulative update
- Restart
- Required
- Replaces
- KB5054977
- Replaced by
- KB5064399
| Version | File version | Channel |
|---|---|---|
| 3.5 | 2.0.50727.9179 | General availability |
| 4.8 | 4.8.4790.0 | General availability |
Security
No vulnerabilities are listed for this update.
Downloads (Microsoft Update Catalog)
x64
Windows 10 Enterprise LTSC 2021 / Windows 10, version 22H2
76.2 MB
Arm64
Windows 10 Enterprise LTSC 2021 / Windows 10, version 22H2
47.7 MB
x86
Windows 10 Enterprise LTSC 2021 / Windows 10, version 22H2
47.7 MB
Updated components
28 files changed since the previous update for the same versions.
| Top changed components | Files |
|---|---|
| .NET runtime (CLR) | 18 |
Sources
Updated
Cited passages from Microsoft's official notes (2)
-
1.
Addresses an issue with concurrency in TypeDescriptor.GetConverter()issue in TypeDescriptor GetProperties() and GetConverter().
support.microsoft.com -
2.
Addresses an issue where interactions between .NET Framework DLL loads and OS code integrity enforcement policy trigger error reporting dialog boxes.
support.microsoft.com
Checked automatically: 8 of 8 checks passed, 2 quoted passages · compared with Microsoft's page on Oct 20, 2026
- Quotes found in the official pages: passed
- Numbers found in the sources: passed
- Vulnerabilities from the dossier only: passed
- Links to allowed domains only: passed
- Every official change covered: passed
- Readable plain text: passed
- Changes confirmed by the file list: passed
- Sources agree: passed
A second AI read the text against the sources: correctness 5/5, clarity 4/5, completeness 5/5. How we work
Published by The Update Bureau. Written with AI from Microsoft's own documents, checked by rules and a second AI. How we work · Report a mistake