After installation, iMovie 10.1.6 must download content packs. Go to iMovie -> Preferences -> Download Additional Content. Ensure you have a stable internet connection.
iMovie 10.1.6 prefers optimized media. Go to File -> Consolidate to convert your footage into proxy media. Additionally, ensure you are not editing 4K video on a spinning hard drive (use an SSD or external SSD instead). imovie 10.1.6 download
: Sign in with the Apple ID you previously used to download iMovie. After installation, iMovie 10