I very rarely tend to browse my music library in iTunes, (which I use on Windows XP for ripping/tagging CDs), since I mostly browse/play back with either foobar2000 (headphone system) or Sonos (big-rig). However while fixing the tags on a disc I had ripped the other day I noticed something very strange.
Lots of tracks had a little '!' icon in the left-hand column of the library view and if I tried to play them I got the message 'The song XYZ could not be used because the original file could not be found. Would you like to locate it?'
I searched around but couldn't find any of the 'missing' tracks on the hard disk despite the fact that I know for a fact they have existed as I have played many of them several times, and they are still indexed in Google Desktop Search. In other words it is not just the indexes (indices?) that have become corrupt, the underlying objects have actually disappeared. They are not in the recycle bin so they haven't been deleted by any 'earthly' means.
Half an hour and a lot of head-scratching later it finally clicked. All the 'missing' tracks had an 8-bit character (what North Amercians sometimes call 'special' characters, presumably because they're jealous), I mean characters like '