Render files are the video files that Final Cut Pro creates when you make adjustments to your video clips. Add a filter or transition, crop the image change the clip's speed, and Final Cut Pro has to create brand new video files using your original media and applying the changes. When the video is played in the project timeline, the render files are played in place of the original video clips, where you have added effects. But what do you do if the render files become corrupt? Or when projects are completed and you want to back them up without the render files?