July 20, 2021-KB5004335 Cumulative Update Preview for .NET Framework 3.5 and 4.7.2 for Windows 10, version 1809 and Windows Server, version 2019

Release Date:
July 20, 2021

Version:
.NET Framework 3.5 and 4.7.2

The July 20, 2021 update for Windows 10, version 1809 and Windows Server, version 2019 includes cumulative reliability improvements in .NET Framework 3.5 and 4.7.2. 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.

Quality and reliability improvements

CLR₁

- In scenarios with both high numbers of assemblies and high numbers of GC heaps, Server GC can encounter serious lock contention during generation 2 GCs. A config switch has been introduced as a workaround. It can either be enabled from a .config file:

<configuration>
<runtime>
<GCStaticsNoLock enabled="true"/>
</runtime>
</configuration>

Or by setting environment variable COMPLUS_GCStaticsNoLockto a non-zero value. If the config switch is not enabled, behavior is unchanged compared to previous versions.

₁ Common Language Runtime (CLR)

Additional information about this update

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

5004414 Description of the Cumulative Update Preview for .NET Framework 3.5, 4.7.2 and 4.8 for Windows 10, version 1809 and Windows Server, version 2019 (KB5004414)

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)	No	You can import this update into WSUS manually via 5004414. See the Microsoft Update Catalog for instructions.

File information

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

Prerequisites

To apply this update, you must have .NET Framework 3.5 or 4.7.2 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

Help for installing updates: Windows Update FAQ
Protect yourself online and at home: Windows Security support
Local support according to your country: International Support

Known issues in this update

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