Windows 10: KB4601554 Cumulative Update .NET Framework 3.5 and 4.8 for Windows 10

May 11, 2021 - KB4601554 Cumulative Update for .NET Framework 3.5 and 4.8 for Windows 10, version 2004, Windows Server, version 2004, Windows 10, version 20H2, Windows Server, version 20H2, and Windows Server 21H1

Release Date:
May 11, 2021

Version:
.NET Framework 3.5 and 4.8

The May 11, 2021 update for Windows 10, version 2004, Windows Server, version 2004, Windows 10, version 20H2, Windows Server, version 20H2, and Windows Server 21H1 includes cumulative reliability improvements in .NET Framework 3.5 and 4.8. We recommend that you apply this update as part of your regular maintenance routines. Before you install this update, see the Prerequsites and Restart requirement sections.

Quality and reliability improvements

CLR1 - Addresses an issue where the entire process would be torn down when a NullReferenceException propagated out of an exception filter.
- Addresses an issue with slowdowns that could occur when making large numbers of devirtualized calls into MarshalByRefObject-derived code. WPF2 - Addresses an issue with lag responding to typing in TextBox, when spell-checking is enabled that was introduced in an update earlier this year.
- Addresses an issue with a leak of touch-related resources, including OS handles, when closing a window. The leak only occurs when a touch device is active, and only for windows whose HwndSource is created directly by the app.
- Addresses a crash when docking a window within Visual Studio, or, more generally, disposing an HwndSource whose RootVisual is null. Winforms - Addresses an issue in ComboBox drop down item bounding rectangle as exposed to the accessibility tools, where we did not take into account that some items might be scrolled out of view, we had always started counting items from the first visible one, and thus item rectangle location was incorrect.
- Implemented ScrollItemPattern (IScrollItemProvider (uiautomationcore.h) - Win32 apps | Microsoft Docs) for ComboBox drop down items. 1 Common Language Runtime (CLR)
2 Windows Presentation Foundation (WPF)

How to get this update

Install this update

Release Channel Available Next Step Windows Update and Microsoft Update Yes To download and install this update, go to Settings > Update & Security > Windows Update, and then select Check for updates. 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 10, version 2004, Windows Server, version 2004, Windows 10, version 20H2, Windows Server, version 20H2, and Windows Server 21H1
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 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

• Help for installing updates: Windows Update FAQ
• Protect yourself online and at home: Windows Security support
• Local support according to your country: International Support

Known issues in this update

Microsoft is not currently aware of any issues in this update.


Source: https://support.microsoft.com/en-us/...3-226f7798225a

Direct download links for KB4601554 MSU file from Microsoft Update Catalog:

Download KB4601554 MSU for Windows 10 v2004, 20H2, and 20H1 32-bit (x86) - 41.6 MB

Download KB4601554 MSU for Windows 10 v2004, 20H2, and 20H1 64-bit (x64) - 65.2 MB

Download KB4601554 MSU for Windows 10 v2004, 20H2, and 20H1 ARM64 - 41.6 MB

:)

 

KB4601554 Cumulative Update .NET Framework 3.5 and 4.8 for Windows 10

Source: https://support.microsoft.com/en-us/...3-226f7798225a


Direct download links for KB4601554 MSU file from Microsoft Update Catalog:

Download KB4601554 MSU for Windows 10 v2004 and 20H2 32-bit (x86) - 41.6 MB

Download KB4601554 MSU for Windows 10 v2004 and 20H2 64-bit (x64) - 65.2 MB

Download KB4601554 MSU for Windows 10 v2004 and 20H2 ARM64 - 41.6 MB

 

Cumulative Update KB4514359 .NET Framework 3.5, 4.8 Windows 10 Sept.10 Win Update

Update: Cumulative Update KB4522738 .NET Framework 3.5, 4.8 Windows 10 Sept.26

Cumulative Update KB4522739 .NET Framework 3.5, 4.8 Windows 10 Sept.26

 

KB4586876 Cumulative Update .NET Framework 3.5, 4.8 Windows 10 Jan. 12 Win Update

Phil,

This might all be pretty confusing now.

I suggest

1 Turn on updates for other MS products - my post #22
2 Run WU to see if it now shows that KB4586876 .Net update as being required

3.1 If WU lists it then install it.
4.1 If it installs and there are no remaining problems, stick the kettle on.

3.2 If WU still does not list it then use that .Net fixer tutorial I gave you a link to - my post #18
4.2 If the problem defies the fixer tool then study the Ghot guidance in that other thread I gave you a link to [ - my post #18] and consider Ghot's suggestion of re-installing the runtime [his post #21].
5.2 If it refuses to install, try reinstalling v3.5 - Install .Net Framework 3.5 - TenForumsTutorials The update is for both 3.5 & 4.8 but I suppose there's a chance that reinstalling 3.5 would give something a kick up the pants enough to get it all working.
6.2 If it still won't play, consider unloading then reloading both .Net entries in CP, P&F, Turn Windows features on & off. We used to do that for WMP in Windows 7 so it is a pretty well-established method but I have not seen anybody apply it to .Net entries before so you might want to discuss it further before doing anything about it.

Best of luck,
Denis

12:29 - I have now finished fiddling with this post.