If I have an MP3 or a wav file that I know is a working, undamaged file
(plays in other programs), but for whatever reason Audition shows as raw
pcm or unsupported, is there anything I can do to "fix" it so audition
likes it?




Invariably, this happens because the header in the MP3 is corrupted or incomplete. Most players take it on trust that if you say it's an MP3, then it really is, and the decoder just gets on with it. But Audition is, and has always been, very fussy about this. The only fix isn't good - as Ozpeter says, you have to degrade the file by opening it (IIRC, you should be able to get Audition to treat the RAW file as MP3 if you try hard, I think, but I haven't done this for ages), and then resave it. Audition will then give it a correct header.