We have a VB.NET application which was originally developed with the target framework as .NET Framework 4.5. However, because the client wants it to also run on Windows XP, we were forced it to change to .NET Framework 4. The solution is in this link. Just follow the steps on the Workaround section. I also copied the steps below to save you time from opening another page.
However, of course, if the current program requires the features that .NET Framework 4.5 offers, then you have no other choice but to re-program to support Windows XP (if the client doesn’t want to upgrade their computers and is willing to pay again to support Windows XP).
The simplest workaround is to edit the modeling project file to ignore target framework version mismatches as follows:
1. Unload the modeling project by right clicking on it in Solution Explorer window and choosing Unload Project.
2. Open the project file into the editor by right clicking on it in Solution Explorer window and choosing Edit projectname.modelproj.
<PropertyGroup> <ResolveAssemblyReferenceIgnoreTargetFrameworkAttributeVersionMismatch>true</ResolveAssemblyReferenceIgnoreTargetFrameworkAttributeVersionMismatch> </PropertyGroup>
4. Save the project file.
5. Right click on the modeling project in Solution Explorer and choose Reload Project.
6. Validate your architecture in the usual way.