I have a family of 4. We all use the same Apple ID, and share music, apps, movies, etc. Up until now, I've always managed everyones iPhone, iPad backups using my iTunes account/login. I've recently decided to set up separate user accounts on our iMac (4 total). The main issue I'm having with this set up is with iTunes! I've followed Apple's recommended settings for this, however I can't seem to figure out how to stop getting duplicate song files. Example: I buy a song while logged into my account on the iMac, everything is good. Then I log into my kids account and the song is not showing in their library. So, I select "add to library" and then I get 2 copies of the song. OR, I use the sharing feature, so their iTunes looks at mine to "add new content" and the same thing happens...DUPLICATES. I have all their accounts' advanced settings to not copy files to iTunes Music folders....but yet it still does. 99% of the time, I'll be logged onto the iMac; therefore, I'll get all songs, apps, and books downloaded automatically with the Store setting. What I'm looking for, is a way for everyone else's login on the iMac to reflect exactly what my Library shows without making duplicates (for HDD space consideration). Does anyone have any suggestions/solutions?