Update for the .NET Framework 4.6, 4.6.1, 4.6.2, and 4.7 on Windows Server 2012 (KB4038921): August 15, 2017

Applies to: .NET Framework 4.6.1.NET Framework 4.6


This August 2017 Update for Windows Server 2012 fixes an issue in the .NET Framework 4.6, 4.6.1, 4.6.2, and 4.7. 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.

Issues fixed

Common Language Runtime (CLR)

  • Applications that run on the .NET Framework do not respect the settings that are specified in the registry for AppContext switches. Regardless of the registry option setting for an AppContext flag, the application behaves as if the value specified is set to "false."

How to get this update

For Windows Server 2012

This update is available by manual download only.

Manual download

To get the stand-alone package for this update, go to the Microsoft Update Catalog website.


To apply this update, you must have the .NET Framework 4.6, 4.6.1, 4.6.2, or 4.7 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.

File information

Applies to

This article applies to the following:

  • Microsoft .NET Framework 4.6, 4.6.1, 4.6.2, and 4.7 when used with:
    • Windows Server 2012