Known issues when you upgrade .NET Framework from version 4.5.2 to 4.6 or 4.6.1 on Windows Server 2012

This article helps you resolve the problem where Microsoft .NET Framework applications can't run when you upgrade .NET Framework 4.5.2 to .NET Framework 4.6 or 4.6.1.

Original product version:   Windows Server 2012, .NET Framework 4.6.1, 4.6, 4.5.2
Original KB number:   4340191


When you upgrade from a fully updated system that is running on .NET Framework 4.5.2 to .NET Framework 4.6.1, you may experience issues when you run .NET Framework applications if you don't download and install updates that apply to .NET Framework 4.6.1.


Consider the following scenario:

  • You use .NET Framework 4.5.2 on Windows Server 2012.
  • You have installed all the latest updates that apply to .NET Framework 4.5.2. This includes the May 2018 updates 4096494 and 4095518, or any later updates.
  • You download and install .NET Framework 4.6 or 4.6.1. However, you don't immediately install updates that apply to .NET Framework 4.6 and 4.6.1.

In this situation, some components of .NET Framework 4.6 or 4.6.1 are not upgraded as expected. This causes some .NET Framework applications not to start or run correctly.


To resolve this issue, try one of the following methods.