I downloaded the Mac OSX 10.4.11 update anthe subsequent Itunes update and when I went to my external hard drive and tried to download music on a new hard drive, many (hundreds) of songs were missing. Some were from mixes and other sources from friends but THE BULK of the material was bought from Itunes or from cds. Why would this happen? Any help is appreciated. I assume this is some sort of user error but I can't find the music. Just to be sure, my current mac is the ninth Apple computer I have owned and fourth Ipod, so I am not a total novice, but totally confused.