I have a MZ-M100 and I'm using Hi-MD Music Transfer for Mac Ver.2.0 and it works beautifully both ways. Uploading and downloading from and into the mini disk player (WAV files). I think everyone should ignore Sony's claims, and just see what the program realy does. Don't use the import button. Just drag the files into and from a folder on your desktop and onto and from the Hi-MD Music transfer screen directly. Can anyone figure out what the advantages are of the new MZ-RH1 over the older MZ-M100, when interface with Mac and PC are identical?