May 11, 2021-KB5001841 Cumulative Update for .NET Framework 4.8 for Windows 10, version 1607 and Windows Server, version 2016

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 Learn) for ComboBox drop down items.

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 1607 and Windows Server, version 2016

Classification: Updates