Hmmmm. You've tried most of the diagnostics that are used to isolate the cause of the conflict. However, you used Time Machine rather than reinstalling through the app store. You want to do an update of iMovie. Therfore, I would definitely update your iMovie 10.1.1 to the highest version that can be used with Sierra. Use this procedure:
To update/redownload iMovie 10, to highest version that will run on your operating system, drag your iMovie 10 app from the Applications folder into the trash, but do not empty the trash. Sign in to the app store and open your purchases folder by clicking on your name at the bottom of the app store side bar. You will see your purchases displayed, including iMovie
10. Redownload/update iMovie from there. If not successful, drag your present iMovie app out of the trash and return it to the
Applications folder.
-- Rich