I'm using the public betas of El Capitan and iOS 9. I shot the video on my 6 plus. Get through the editing process ok (except visibility of waveforms for audio associated with video is inconsistent). When I go to export the project to a file, the progress indicator will advance a little bit and the fans kick on. Then the fans kick off and the file never completes. I can still edit project and view media in iMovie at this point. If I try to cancel the export iMovie becomes unresponsive. Anyone else having a similar issue?