Green screen editing Final cut pro

I have had several editors ask why there green screen edits came out with a black background after exporting them?
If you are producing a green screen video for a website developer or anyone else. If you are not placing the back ground behind the talent that you have used the chroma key to get rid of the green back. In other words they simply want no background on what is delivered. Remember this very important point. Do not render the video before you export. If you do the final exported product will simply have a black background.

ONCE AGAIN DO NOT RENDER BEFORE EXPORTING IF YOU WANT NO BACK GROUND.