If the specific minidisc is unreadable in another player, and if this is a minidisc that has been used repeatedly and often, it's possible that the TOC (table of contents) has become corrupted and unreadable. This is, unfortunately, a danger with any device that writes files to any medium, be it fixed computer drive, CD-RW, or even a flash drive. It the minidisc is playable in another player, it might be a hardware issue with a specific Minidisc player. I've used Minidisc for ten years, however, and even have a few discs that I write over numerous times. Over the years and with multiple blanks, I've experience a failure in only one disc (though I've had a couple of players/recorders begin to act squirrely). And rarely, I've had a disc or two that can't be played in a specific player. So, in my experience, the Minidisc format is the most durable and reliable I've ever worked with--certainly more reliable than your typical computer hard drive, and definitely more durable than CD-R's, which tend to deteriorate over time.