I have discovered this on another support forum so I can't take credit for it but, incredibly, if you put a tape in your dcr-trv17 sony camera or similar cameras, close the tape door, and, with the camera off...uh...smack the camera pretty hard a couple times. Then eject the tape, reinsert it and turn the camera on. The C:31:23 error message should go away. I know it sounds crazy and I was unsure if I should beat my camera up when it wasn't working but it really did work. Good Luck.