I was trying to update my main app code to utilize the .Net Framework 4.0 and this happened:
The Problem: I could find no obvious way to update the mscorlib reference in my solution, so I decide to simply delete it and add it again, and hope that it magically updates to the most recent version. This is actually what usually happens with Visual Studio. However, I delete the mscorlib reference, and I am unable to add it back again, I get the error message telling me that mscorlib is already included in the project.
The Cause: This is a known problem in Visual Studio.
The Solution: I just went into my project (.csproj) file and added the following line
<Reference Include=”mscorlib” />
And that fixed it. I still have no idea how to make it use the most recent .Net Framework though.
This post originally appeared on the Stronico blog – with the absorption of Stronico into Digital Tool Factory this post has been moved to the Digital Tool Factory blog