Visual Studio 2010 error: "Project Target Framework Not Installed" when opening a .NET 4.0 project

Question

I am experiencing a rather disconcerting issue with one of my development machines that I hope someone can advise me on.

I have a large Visual Studio 2010 VB solution, targeting the .NET Framework 4.0 which opens and works just find on numerous Visual Studio 2010 installations - except one. The 'error' (more a message) when opening the solution says:

Project Target Framework Not Installed

The VB project is targeting '.NETFramework,Version=v4.0", which is not installed on this machine. You must download this framework in order to open and build this project. In order to proceed, you must select an option below.

Here's a screenshot with the full context:

http://img507.imageshack.us/i/errorlc.jpg/

I have tried:

1. Repairing (didn't fix), uninstalling and reinstalling Visual Studio (didn't fix)
2. Repairing (didn't fix), uninstalling and reinstalling .NET Framework 4.0 (didn't fix)

Retrying step number 1 again after step number 2 (didn't fix).

What worked temporarily was when I used a .NET Framework removal tool in order to remove all traces of the .NET Framework 4.0 from the machine (including the registry) and then installing the .NET Framework 4.0 again. However the error has returned.

I'm not sure if this is a problem with some .NET Framework 4.0 file corruption, something within Visual Studio or simply that Visual Studio cannot find the .NET Framework 4.0. (I have found several possible 'explanations' but nothing that resolves this issue.

The machine is running Windows 7 (64 bit).

Any ideas towards troubleshooting this issue would be warmly received!

Answer 1

I solved this issue for myself by downloading the appropriate Developer targeting pack. I made the mistake of trying to download the Runtime one, which apparently does not include the Visual Basic plug-in that you need.

I am using .NET Framework 4.5.1, and this is the link to the page I downloaded from:

http://msdn.microsoft.com/en-us/library/5a4x27ek%28v=vs.110%29.aspx