An anonymous reader writes: Early adopters of Apple Music are warning others they could get more than they bargained for if they intend to download tracks for offline listening. Since Apple Music is primarily a streaming service, this functionality necessitates turning on iCloud Music for syncing purposes. The way Apple syncs files is to scan your library for known music files, and if it finds one, the service gives your account access to Apple's canonical copy. Unfortunately, this wipes out any custom edits you made to the file's metadata. For those who have put a lot of time into customizing their library, this can do a lot of damage to their organizational system. Apple's efforts to simplify and streamline the process have once again left advanced users with a difficult decision to make.