Thanks Peter for the speedy reply. I'm using version PictoExe 6.5 de luxe on Windows Vista. Ive tried both mp3 and wav , put together with Audacity. I add music using the Project options : Add Music, spread slides along music. Ive tried copying the same slides into a new project ....no luck , and the error message comes up as soon as I start the new project. Old projects are working fine, and I've also tried the music with another set of slides...no problem. Best wishes Bill