I had hoped to never mention IT on this site, but I’ve run iTunes on an external drive for a number of years with numerous problems and got frustrated by how little help I could find on the internet. Being a firm believe that complaining without fixing an issue is just whining, I thought I’d post my tips and tricks below.
Firstly, I’ve chosen to store my music on an external hard drive (generally NAS) for quite a few years now. There’s quite a few benefits to this approach: You don’t have to worry about your music collection growing (since you can just keep adding hard drives); you can access your music from any computer on the LAN; you can easily take your music with you by just picking up the drive.
Like many people, iTunes is my media player of choice. iTunes supports using a custom folder for music (under Advanced) but unfortunately it has a few very poorly thought out implementation details that mar its effectiveness with a remote music collection.
iTunes stores metadata about its music collection in an XML file, including whether the track is where it is supposed to be. Should the drive not be available (off the network for instance), iTunes will unhelpfully decide that every track in your music collection is now orphaned.
Fortunately, it is possible to force iTunes to realise its mistake without manually double clicking on every single file. Firstly, turn off ‘keep iTunes folder organised’; next turn it on again; and finally choose ‘consolidate library’.
Another trick is that iTunes sometimes forgets about some of your albums. I haven’t fully diagnosed what causes this yet except that it happens most regularly with music names containing non English characters (e.g. accents). My suspicion is that it relates to how Apple implements special characters over NFS differing from how it implements them when the drive is direct-attached, though I’ve also had the issue after iTunes crashes.
The solution is fairly simple. iTunes has quite good duplicate detection with silent skipping during import, so simply ‘import’ your entire music folder and you should only end up importing the files that iTunes forgot about.