I have a Sony DRX810UL (by it’s label, although Nero sees it as a DRU810A) external attached by firewire. Audio CDs are only recognized by Nero (SmartStart 126.96.36.199, Burning ROM 188.8.131.52, came with the burner). All audio discs are seen as blank by Itunes, Zune, RealPlayer, WMP).
It sounds like a uninstall/reinstall drivers issue, but I’m not sure. Is this something Nero software does to the drives?