You're right, I did solve it. After fighting with it for 2 or 3 hours and not getting anywhere I took a break. Then when I got back at it, I noticed that there were two locations in the program where you can identify which mp3 file to use as the audio track. It had been so long since the previous project, I was only using the main screen (lower right hand corner) and not even bothering to go into the project options menu and clicking on the music tab. So all those times I had been changing the audio file, switching from mp3pro to mp3, remixing in cooledit, switching to wav... it was all for not. I was never actually changing the audio file in the project, I was just changing what audio file was listed on the main screen (which, from what I gather, doesn't affect the project at all). Ah silly me! But they all pretty much sounded the same (22k versus 44.1k... 128kbps CBR versus 96kbps VBR etc) so it took me a while to figure it out. But the problem stemmed from using a variable bit rate (VBR) mp3pro file instead of a straight ahead, constant bit rate (CBR) mp3. Much like WinAmp, I don't think PicturesToExe can determine the correct length for a VBR mp3 file right at the beginning. So this 40 minute narration file looked like it was 20:27 long at the start, and the project allocated that much length to the timeline instead of the real length. So in summary, my suggestion to myself and anyone else is: "Don't use variable bit rate mp3 files" Thanks everyone for your help.