I had an Akai 2800 in the past.. I think the problem lies with the SCSI chain.. if I remember correctly, a lot of time has passed, in the SCSI chain there is a master and the rest slaves. If you connect the Mac that acts as master it sees all the units as slaves, this is probably why it doesn't recognize the zip cassette and asks you to format it, because it isn't recognized by the Mac. the only way to use the zip is to disconnect the mac in this way the sampler acts as the master and recognizes its format, or use the connected zip by formatting the cassette in a format recognized by the mac, therefore not Akai. Or have a program on your Mac that recognizes the Akai format, open it before inserting the zip cassette, tell it to search for Akai format and then insert the zip cassette. this is according to my experience.