Chainsaw, I appreciate your quick reply and help but I'm not sure if it's applicable (my overall understanding of all things computer is rather limited but...) Some files that I can't play on Windows Media for eg. I can "Add" to be burned and Express + Burn immediately decodes them. So, no problem there. As you listed, numerous formats are accepted by Express Burn + and immediately decoded and so it tells me. When adding a file, it first says it's decoding it (if it has to) and then says it's normalizing volume. (Not sure what it's doing there as the end result is still different volume levels over the tracks/files I burned.) However, in trying to outsmart the little devil, I have occasionally highlighted all the tracks, then pressed the Normalize Volume - THEN, and only then, do I get the codec error message.