I was getting the below message from Visual Studio 2010.
\"This project is incompatible with the current version of Visual Studio\"
I Resolved the issue by deleting the files in the below folder
%localappdata%\Microsoft\VisualStudio\12.0\ComponentModelCache
Source: https://forums.xamarin.com/discussion/70388/how-to-fix-incompatible-issue-after-visual-studio-2015-update-3