Visual Studio 2010 Only Upgrade One Of Eleven Of My Projects To .NET 4.0

I've just converted my ASP.NET MVC1 VS2008 .NET3.5 solution to ASP.NET MVC3 VS2010 .NET4.0. The solution contains 11 projects, 5 of which are test projects and 1 of which is a web project that is what the solution is built from.

My problem has been (aside from all the other problems that you have when upgrading anything) that the visual studio conversion tool converting from VS2008 to VS2010 said that it would upgrade my project files to .NET 4.0. I was all like 'Great, what could go wrong?' quite a lot of stuff apparently.

The main thing is that only the web project was upgraded to .NET 4.0 so none of the other projects ca开发者_StackOverflown reference it. Or at least, they reference it but can't use anything within it and complain at me a lot.

The only upgrade .NET from 3.5 to 4.0 I've seen out in the world is Microsoft's one that says just run the VS2010 upgrade tool on it and it'll all be fine, so does anyone know any way I could fix this or manually upgrade to .NET 4.0?

Regards, Harry

It sounds like something has gone wrong with the upgrade to me, I've upgraded solutions with 4/5 projects to .NET 4.0 without issue. Can you restore a backup and try again?