I just have to say thank you to @cybercase for making this awesome app available to the minidisc users of the world!! I have just tried it with my MZ-N520 on my iMac ruining OSX 10.13.6. (the iMac is a 2010, so it't can't be upgraded further). Converted from mp3, but got an error when I tried to convert apple lossless. Anyway, I love the fact that minidisc as a format still thrive and that you found the time to make the app happen Stefano:)
Best wishes from Amund