The official Apple party line is that you can only use them on their respective HD FS, although they admit you can re-format the Win version with HFS+ to work on the Mac. What Brian says here makes more sense (i.e. leaving it on Fat32 for both OS) but it would be nice to have somebody who owns one confirm it before I shell out the readies! Perry Mitchell -----Original Message----- From: Brian >>I tried to use my iPod on my Mac then a PC. Was that a Mac iPod or a Windows iPod? From what I understand, you can use a windows iPod on a mac or PC interchangeably, you just can't boot your mac from the iPod.