I've reported in the past about the bass part dropping out with rendering. In my case, only the bass track. I'm using 2012 with the maximum stuff. I send the rendered file to the same folder as the BIAB file. In fact, yesterday I made 23 mp3 files for a friend who's a solo act. Out of this group, 4 of the files had bass dropouts. When this happens, the bass part disappears about halfway through the song---never at the first of the tune. I simply rendered those 4 tunes again from the same BIAB files and they turned out fine. Something's glitchy, but I still love the program.