Hi, I just did a recording on Skype and transferred it to FCPX and there was no sound. I found a way to fix that problem by extracting sound adding to the video and making it a compound clip. HOWEVER, now I have finished editing, exported it (mp.4) and the sound disappeared!!

Hi - Since you got the sound to play by extracting it I'd guess it might be something to do with how the extracted audio is being handled within the compound clip, maybe an audio-related export setting that needs to be changed, or an audio format issue [unless there's some inherent issue with the original audio that wouldn't play until it was extracted].. I don't have FCPX [I am an audio guy, but not a video editor] but I've attached a FCPX course to the top of this thread [More Info] specifically on audio editing in FCP -- there are videos on compound clips and exporting, maybe there'll be something useful in there, or maybe a FCP guru will have a thought on a potential cause.. Assuming you've done the usual troubleshooting steps [like hard shutdown/restart], a couple of possible troubleshooting steps might include re-importing the original video into a new FCP project, duplicating what you did to get the audio to play, and then [without taking the time to do all the editing] doing a quick test export to see if the issue still happens, or if it's specific to something you may have done while editing.. You could also try the same procedure with different video -- if you create a compound clip with the audio in a different video using the same procedure and a test export works, then the problem may be with that specific audio recording; if it has the same issue, then the issue might be procedural [something specific with how the audio is handled in compound clips]..