I have the ND-3550A. Nearly all drives, and the NECs are no exception, do not like certain makes of media. Usually this can be fixed with a firmware update. I recommend using a firmware update from rpc1.org, preferably a Liggy's and Dee's because those enable bitsetting and do other nice stuff. The standard advice applies: Always use media that's made in Japan, except for Verbatim, which is also good. NEC's, in particular, don't like some kinds of cheap media like Ritek. Edit: If you go with the Liggy's and Dee's get the "Liggy's ND3550 Bitsetting Firmware 1.06" at http://liggydee.cdfreaks.com/page/3550/ Don't mess around with the others.