I just moved my entire music library from my old PC paperweight to my new MacBook. So I plugged in my iPod to the latter this afternoon and engaged in the sync process. But when I view the 'Pod by clicking "devices", then "iPod", and looking at "summary", there's an error message next to "update". It says "Only Macintosh-formatted iPods can be updated." What does this mean? Should I erase everything off the iPod and start again? Is it possible to format it for a Mac after two years of PC service? (I have a fourth generation 20gb white iPod classic.) Thanks!