If you get this error:
Unable to read the project File <path.to.project>.csproj.
C:\<path>\<to>\<projecct>\Project.csproj 77, 11): The imported project “C:\Microsoft.CSharp.targets’ was not Found. Confirm that the path in the <Import> declaration is correct, and that the file exists on disk.
As shown in this screen shot …
Take a look at your project file. Open it in a text editor (such as NotePad++) and look for the import statement.
Mine looked like this:
How to fix
Change the MSBuild Property $(MSBuildToolsPath) to $(MSBuildBinPath) and the project should load.