I am running Sierra, I have iMovie 9, I want the latest version that can work with Sierra which would be 11, how do I do that?

Since you are saying that you had acquired iMovie 10 on at least one of your computers, you can sign in to the app store with the Apple I.D. that you used to acquire iMovie 10, and update it using the procedure that I described in my earlier post.

-- Rich

There is no iMovie 11. iMovie 9 is iMovie '11 (with an apostrophe). iMovie 10.1.14 is the latest version. Unless you had iMovie 10 on your computer at one time, but perhaps deleted it, you will not be able to update to current iMovie 10. or any iMovie 10. If you did have iMovie 10 on your computer at one time, then you can use this procedure to get the most current version:

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 out of the trash (if you moved it there) and return it to the Applications folder.

It looks like you never did have iMovie 10, so not having purchased it before you won't be able to get it now.

Having said that, take a look at this link for some possible hope:

https://apple.stackexchange.com/questions/301762/is-it-possible-to-download-acquire-imovie-10-1-6/378247#378247

And this one, particularly the last three posts that discuss the above link:

https://discussions.apple.com/thread/251259186

-- Rich

Great! Glad it worked for you. :)

So, do you mean that the two links I sent didn't connect to the destination site, or that the solutions in the site didn't work?

-- Rich