I have been developing an application in VS2010 and compiling it for the .NET 4.0 as the target framework. After integrating a library into my application, I get the followi
Open your .resx file with the XML editor instead of the resources editor, and search for System.Windows.Forms, Version=4.0.0.0. There should be 2 instances of this string. Replace 4.0.0.0 with 2.0.0.0 and save the file. Your resources should work correctly now.
Note that you can also go back to .NET 4 and try to add the following to your App.config to allow older assemblies to run on the new runtime: