In my case I was using the wrong version of MSBuild.exe
.
The version you need to use depends on what version of Visual Studio you used to create your project. In my case I needed 14.0 (having used Visual Studio 2015).
This was found at:
C:\Program Files (x86)\MSBuild\14.0\Bin\msbuild.exe
You can look under:
C:\Program Files (x86)\MSBuild
To find other versions.