Updates to .NET Framework 2.0 by using Windows Update may cause some .NET Framework applications to crash

This article helps you resolve the problem that updates to Microsoft .NET Framework 2.0 by using Windows Update cause some .NET Framework applications to crash.

Original product version:   .NET Framework 2.0
Original KB number:   2677528


Consider the following scenario:

  • You install an update for .NET Framework 2.0 by using Windows Update.
  • You run a .NET Framework 2.0 application, a .NET Framework 3.0 application, or a .NET Framework 3.5 application.
  • You leave the computer on which your application is running idle for some time. When the computer is idle, the native images for the .NET Framework are automatically regenerated.

In this scenario, when you resume work in the .NET Framework application, the application may crash. Additionally, you may receive an error message that resembles the following one:

Exception type: System.IO.FileLoadException
Message: Loading this assembly would produce a different grant set from other instances. (Exception from HRESULT: 0x80131401)


To work around this problem, use one of the following methods:

  • Restart the application.

  • Run the Native Image Generator (Ngen.exe) tool to update the native images on your computer, and then restart the application. To update the native images, at a command prompt, run the following command by using administrative credentials:

    %WINDIR%\Microsoft.NET\Framework\v2.0.50727\ngen update

    Additionally, on a 64-bit computer, run the following command:

    %WINDIR%\Microsoft.NET\Framework64\v2.0.50727\ngen update

More information

For more information about the Ngen.exe tool, visit Native Image Generator (Ngen.exe)