That's what I had trouble with for a couple months. What I eventually did was drag the Unix executable into the Terminal and hit enter. Unfortunately since Apple is dumb, they'll say it wasn't opened because of privacy issues, but all you need to do is go into System Settings >> Privacy & Security (You'll need to scroll down) >> Then it'll show you a message box saying AudioButcher wasn't opened because it couldn't be confirmed it was free from malware; just hit the "Open Anyway" box. You'll need to drag the Unix executable into the terminal again and this time it'll have a pop-up saying to open anyway, and it'll ask you for your password or Touch ID to verify. After you've done all that, it should open!