I have used CD-R, CD-RW, DVD+R, and DVD+RW to play MP3s on my unit. With either format, when I turn the head unit/car off, next time I turn it back on, it would resume from the last song played, but at the beginning of it. That was my major annoyance with the unit, but it was something I got used to over time. Sounds like yours is behaving a little strange. But given the quality of these units, it's not something out of the ordinary. I have questioned the quality of my unit a few times and now it is to the point where I am using an MP3 player plugged into the AUX port because I simply can't trust how long the laser pickup is going to last on these units. Last thing I want is a busted laser because that is the only decent way to play video files.