i can't update my iMovie version 10.15.6

Hi, Tishourna,

You didn't mention the steps that you were taking to update iMovie, or what happens when you try. In any event, try this procedure:

To update/redownload iMovie 10, 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