Preview of Quality Rollup for .NET Framework 4.8 for Windows 8.1, RT 8.1, and Server 2012 R2 (KB4519567)

Important

• All updates for Windows 8.1, Windows RT 8.1, and Windows Server 2012 R2 require that update KB 2919355 is installed. We recommend that you install update KB 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.

¹ Windows Presentation Foundation (WPF)
² Common Language Runtime (CLR)

• 4520408 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 (KB4520408)

Symptoms:

After applying this October 15^th Preview of Quality Rollup for .NET Framework 4.8, some ClickOnce applications and applications creating the default AppDomain with a restricted permission set may observe application launch or application runtime failures, or unexpected behaviors. The observable issue is the System.AppDomainSetup.TargetFrameworkName (https://docs.microsoft.com/en-us/dotnet/api/system.appdomainsetup.targetframeworkname?view=netframework-4.8) is null, leading to any quirks enabling reverting back to .NET Framework 4.0 behaviors.

Workaround:

Customers observing new unexpected failures or functional issues can implement an application setting by adding (or merging) the following section to your application config file:

To resolve this issue, install update for .NET Framework 4.8 for Windows 8.1, RT 8.1, and Server 2012 R2 KB4533004.

Method 1: Windows Update

This update is available through Windows Update. Go to Settings > Update and Security > Windows Update, and then select Check for updates. For more information about how to get preview updates, see Windows Update: FAQ.

Method 2: Microsoft Update Catalog

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

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. Type 4520408 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 updates 4516553.