Hi Lowell, PTE has always been very particular about finding files. It's very easy to think you have saved a file where PTE will find it but then, often after a pause doing while you're doing something else for a few days, it won't appear. There's good advice from Barry as above: 'When making a slide show, create a folder and copy EVERYTHING you use into that folder, then work from there and only there. Your project file and Mp4 should also be in that folder and if you do that, you will have the ability to adjust your show and recreate it any time. Plus you’ll always know where everything is.'