iMovie only exporting to 720p
I've exported videos in my MacBook before to 1080p and 4k, however now when I add 4k videos, everything is defaulting to 720p. I've tested the tricks to go into an old project that's 4k, drag the new video behind it, delete the front video to keep it at 4k, but it goes back to 720p. Then when I undo everything, the video that was once exported to 4k will now only export to 720p.
I created a short 4k video test. I added it to iMovie on my iMac and it will export to 4k. I added it to iMovie on my MacBook and it will only export to 720p.
MacBook Pro 15", macOS 10.12