Hi Tom, thank for suggestion. I play by my mac both files and they go properly.I see that it's necessary some seconds to open. I discoverd, for a case, that my file containing 450 slides,with a vaw audio,555mb, open fast but the audio doesn't play good. Stop and go. So I converted the audio by itune into mp3 and I substituted it into my PTE project.I converted to get mac exe and I found that it plays almost good ( some time the audio has very short stops), but it takes more than 5 min to start!! I'l try to send You a part of it by dropbox.com thank Giancarlo