I've had a similar problem
Similar question: If I want to switch to a new Macbook, how can I import my iTunes library? I have an external hard drive, but I am wondering if I will lose a lot of the details of the tracks (i.e., my ratings, album info etc) by doing that. I assume that I can log into iTunes on the new Macbook with my Apple ID and the material I purchased through iTunes will be available. However, what would happen to the songs I imported from CDs etc?
Wife and I have two iPhone4's with about 1500 songs. They include some iTunes purchases but were mainly songs imported into my PC from multiple sources including my own cd's, before we got the iPhones.
Recently I got an iMAC computer to replace the PC. I backed up the songs from the PC to an external source. I then imported them to the new iTunes in my iMAC. The songs that weren't purchased thru iTunes were imported with the free download, Senuti.com. Now.....when I tried to sync the iPhones to the new iTunes in the iMAC, it synced all the songs only when I went to the music page on iTunes with wife's iPhone 4 plugged in. I first made sure that it was programed NOT to automatically sync when the iPhone was plugged in. Anyway, on the music page, I checked ALL the artists in my iTunes music, then synced them. As I say, all the songs synced between my iPhone and new iTunes (on the new computer).
BUT.....the playlists only partially synced. Even though all the songs were there, only a fraction of songs (maybe 1/10th) ended up in the iPhone's corresponding playlists. I'm not sure why and when I called Apple Help for advice, they tried a couple of suggestions with me, but ultimately had no answer(s). Still I'm, for the most part, satisfied that all my songs are both on the iPhone and the new computer's iTunes.
Thoughts? suggestions?