Security and Quality Rollup for .NET Framework 4.8 for Windows 8.1, RT 8.1, and Server 2012 R2 (KB4515846)

Applies to: .NET

The September 24, 2019, update for Windows 8.1, Windows RT 8.1, and Windows Server 2012 R2 includes cumulative reliability improvements in Microsoft .NET Framework 4.8. We recommend that you apply this update as part of your regular maintenance routines. Before you install this update, see the Prerequisites and Restart requirement sections.

Important

  • All updates for Windows 8.1, Windows RT 8.1, and Windows Server 2012 R2 require that update 2919355 is installed. We recommend that you install update 2919355 on your Windows 8.1-based, Windows RT 8.1-based, or Windows Server 2012 R2-based computer so that you receive updates in the future.
  • If you install a language pack after you install this update, you must reinstall this update. Therefore, we recommend that you install any language packs that you need before you install this update. For more information, see Add language packs to Windows.

Quality and reliability improvements


BCL1
  • Addresses an issue that affects thread contention that occurs in BinaryFormatter.GetTypeInformation by using ConcurrentDictionary to handle multi-thread access.
WPF2
  • 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.
CLR3
  • 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)

Additional information about this update


The following article contains additional information about this update as it relates to individual product versions.
 
  • 4516553 Description of the Preview of Quality Rollup for .NET Framework 3.5, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8 for Windows 8.1, RT 8.1, and Server 2012 R2 (KB4516553)

How to obtain and install the update


Method 1: Windows Update

This update is available through Windows Update. When you turn on automatic updating, this update will be downloaded and installed automatically. For more information about how to get security updates, see Windows Update: FAQ.

Method 2: Microsoft Update Catalog

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

Method 3: Windows Software Update Services (WSUS)

On your WSUS server, follow these steps:

  1. Select Start, select Administrative Tools, and then select Microsoft Windows Server Update Services 3.0.
  2. Expand ComputerName, and then select Action.
  3. Select Import Updates.
  4. WSUS opens a browser window in which you may be prompted to install an ActiveX control. You must install the ActiveX control to continue.
  5. After the ActiveX control is installed, you see the Microsoft Update Catalog screen. Enter 4516553 into the Search box, and then select Search.
  6. Locate the .NET Framework packages that match the operating systems, languages, and processors in your environment. Select Add to add them to your basket.
  7. After you select all the packages that you require, select View Basket.
  8. To import the packages to your WSUS server, select Import.
  9. After the packages are imported, select Close to return to WSUS.

The updates are now available for installation through WSUS.

Prerequisites

To apply this update, you must have .NET Framework 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 4512195.

File information


The English (United States) version of this software update installs files that have the attributes that are listed in the following tables.

Windows 8.1, Windows RT 8.1 and Windows Server 2012 R2


Additional file information

 

How to obtain help and support for this update