KB4601556 Cumulative Update .NET Framework 3.5 and 4.8 for Windows 10 Win Update

    KB4601556 Cumulative Update .NET Framework 3.5 and 4.8 for Windows 10

    KB4601556 Cumulative Update .NET Framework 3.5 and 4.8 for Windows 10

    For Windows 10 version 1909 - May 11, 2021
    Category: Win Update
    Last Updated: 19 May 2021 at 12:27
    May 11, 2021 - KB4601556 Cumulative Update for .NET Framework 3.5 and 4.8 for Windows 10, version 1909, and Windows Server, version 1909

    Release Date:
    May 11, 2021

    .NET Framework 3.5 and 4.8

    The May 11, 2021 update for Windows 10, version 1909, and Windows Server, version 1909 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 1909, and Windows Server, version 1909
    Classification: Updates

    File information

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


    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

    Known issues in this update

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

    Source: https://support.microsoft.com/en-us/...f-ad9e32cbb40f

    See also: https://devblogs.microsoft.com/dotne...ollup-updates/

    Direct download links for KB4601556 MSU file from Microsoft Update Catalog:

    Download KB4601556 MSU for Windows 10 v1909 32-bit (x86) - 44.3 MB

    Download KB4601556 MSU for Windows 10 v1909 64-bit (x64) - 76.7 MB

    Download KB4601556 MSU for Windows 10 v1909 - 44.3 MB
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