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

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

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

    For Windows 10 version 1909 and KB4515871
    Category: Win Update
    Last Updated: 26 Sep 2019 at 12:56

    September 26, 2019 - KB4522739 Cumulative Update for .NET Framework 3.5 and 4.8 for Windows 10 version 1909 and Windows Server version 1909

    Applies to: .NET Framework
    Version:.NET Framework 3.5 and 4.8


    This article describes the September 26, 2019 update for 3.5 and 4.8 for Windows 10, version 1909 and Windows Server, version 1909.

    Additional information about this update

    The following articles contain additional information about this update as it relates to individual product versions.

    • 4515871 Description of the Cumulative Update for .NET Framework 3.5 and 4.8 for Windows 10, version 1903 and Windows 10, version 1909 (KB4515871)

    Quality and reliability improvements

    • Addresses an issue that affects thread contention that occurs in BinaryFormatter.GetTypeInformation by using ConcurrentDictionary to handle multi-thread access.
    • Addresses an issue that affects a WPF ComboBox (or any Selector) within a DataGrid cell that can try to change its selection properties (SelectedIndex, SelectedItem, SelectedValue) when the cell's data item is re-virtualized or removed from the underlying collection. This can occur if the Selector's ItemSource property is data bound through the cell's DataContext setting. Depending on the virtualization mode and the bindings that are declared for the selection properties, the symptoms can include unexpected changes (to null) of the data item's properties, and unexpected displays (as null) of other data items that re-use the UI that was previously attached to the revirtualized item.
    • Addresses an issue in which a WPF TextBox or RichTextBox element that has spell checking enabled crashes and returns an "ExecutionEngineException" error in some situations, including inserting text near a hyperlink.
    • Addresses an issue that affects Per-Monitor Aware WPF applications that host System-Aware or Unaware child windows and that run on .NET Framework 4.8. This .NET version occasionally crashes and returns a "System.Collections.Generic.KeyNotFoundException" exception.
    • Addresses an issue that might cause handle leaks to occur in scenarios that repeatedly load and unload Mscoree.dll.
    • Addresses rare cases that incorrectly cause process termination instead of delivering the expected NullReferenceException result.

    1 Base Class Library (BCL)
    2 Windows Presentation Foundation (WPF)
    3 Common Language Runtime (CLR)

    How to obtain and install the update

    Install this update

    To download and install this update, go to Settings > Update & Security > Windows Update, and then select Check for updates.

    This update will be downloaded and installed automatically from Windows Update.

    To get the standalone package for this update, go to the Microsoft Update Catalog website.

    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.

    Update replacement information

    This update replaces previously released update 4511555 for Windows 10, version 1903.


    See also:
    Brink's Avatar Posted By: Brink
    26 Sep 2019

  1. Posts : 2,829
    Windows 10 Pro X64


    Just finnished installing. Nothing to add.

      My Computers

  2. Posts : 61,909
    64-bit Windows 11 Pro for Workstations
    Thread Starter

    Cumulative Update KB4522739 .NET Framework 3.5, 4.8 Windows 10 Sept.26-kb4522739.jpg
      My Computers

  3. Posts : 1,904
    Windows 10 Pro x64

    Yes, fast and installed fine............
      My Computer


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