Visual Studio 2012 Build failed but no error in error list [duplicate]

Question

I started working on a project in Visual Studio 2012 professional, which has been written in Visual Studio 2010 SP1. In the solution is several projects. In one them is a problem, when I set it as the startup project I have the message: "There were build errors. Would you like to continue and run the last successful build?", but there is no errors in error list (others projects build success if them set as a startup). In the VS2010 there was no problem.

The only problem that I see is: in the Properties -> Settings, I get an error:

"Could not resolve mscorlib for target framework '. NETFramework, Version = v3.5'. This can happen if the target framework is not installed or if the framework moniker is incorrectly formatted."

Answer 1

Close VS2012 and remove the (hidden) .suo file. Removing that file will solve the problem. Set "show hidden files" via Control Panel\Appearance and Personalization\Folder Options.