Visual Studio needs to make non-functional changes to this project

Question

I opened a C# project that was created in VS 2010 SP, with VS 2012. A one-way conversion window appeared where I proceeded with the conversion.

Upon completion I got

Answer 1

If you look into the .csproj file, you will see this:

< Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props"     

 Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />

and

< OldToolsVersion>4.0< /OldToolsVersion>