imovie

You should be able to reinstall iMovie 10.

To update/redownload iMovie 10, drag your iMovie 10 app from the Applications folder into the trash,

but do not empty the trash. (You can skip that step if you had iMovie 10 on your computer before, but deleted it.) 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 from the trash and return it to the applications folder.

-- Rich

In what way didn’t it work? Did iMovie not show in your purchases folder? Did you sign into the app store with an Apple I.D. different from the one that you used to acquire iMovie?

— Rich