I just finished up an iMovie project, and I tried to export it, but every time I click "Share to File", which is what I do every time, but it responds with the Mac "ding" sound, the one that plays when the Mac cannot complete the procedure. It won't let me upload to Youtube directly, or any of the other sharing options. I just get the Mac ding. I have 400 GB of storage left, and the project is only 4 minutes, so it should take up a gigabyte at most. Can someone help?