On newer Apple OS... the Keyfinder Application which installs immediately after Song Surgeon sometimes fails. If you see an error message regarding installation of KeyFinder or key detection doesn't work in Song Surgeon 5, please try the following:
Once
downloaded, using Finder, open your Applications folder. Then with another instance of Finder go to your Downloads Folder, find this KeyFinder binary and grab this file with your mouse and DRAG it to the Applications folder . After that, open SS and check to see if SS now
detects key properly.