The Update BureauKB5056579: Cumulative update for .NET Framework, versions 3.5 and 4.8.1, on Windows 11 24H2 and Windows Server 2025, July 2025. Type-converter concurrency and runtime error dialogs addressed
In short
Addresses .NET type-converter concurrency problems and error-reporting dialogs linked to DLL loading and OS code integrity checks. It adds no new security improvements; devices that already installed it need no action.
Does it affect you? Applies to: Devices running Windows 11, version 24H2, or Windows Server 2025 with .NET Framework 3.5 or 4.8.1 installed.
What changes
Fixes 2 changes
.NET Libraries
-
A concurrency issue involving .NET type-converter lookups is addressed.1
Addresses an issue involving
TypeDescriptor.GetProperties()andTypeDescriptor.GetConverter().
.NET Runtime
-
An issue that can trigger error-reporting dialog boxes during .NET Framework DLL loading and OS code integrity checks is addressed.2
Addresses interactions between .NET Framework DLL loads and OS code integrity enforcement policy.
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
- KB5054979, KB5050577, KB5048162, KB5045934
- Replaced by
- KB5064401
| Version | File version | Channel |
|---|---|---|
| 3.5 | 2.0.50727.9179 | General availability |
| 4.8.1 | 4.8.9310.0 | General availability |
Security
No vulnerabilities are listed for this update.
Downloads (Microsoft Update Catalog)
x64
Windows 11, version 24H2 / Windows Server 2025
71.6 MB
Arm64
Windows 11, version 24H2 / Windows Server 2025
88.1 MB
Updated components
27 files changed since the previous update for the same versions.
| Top changed components | Files |
|---|---|
| .NET runtime (CLR) | 12 |
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