MusiCAD is a windows-only program...I just applied to download MusiCAD and the first thing I read was that it was for Windows, which I’m afraid I don’t have. Is there a version for Mac Yosemite ?
However, it is possible to install a wonderful (free) toolset called Wine on a Mac that will allow you to run (m)any Windows-only programs.
Detailed instruction can be found at: http://winebottler.kronenberg.org/