If you've worked with iMovie before,
you've probably noticed that it saves automatically, all the time.
Usually, this is great news.
But if you want to backup your iMovie project or move it to another computer,
you'll need to understand how iMovie handles your projects
and where it saves them.
iMovie creates a project file with the name
that you give it when you start the project.
You can find this file by navigating to "Movies" and then "iMovie Projects".
The most important thing to understand is that you need this file,
but it does not actually contain any video, photos, or audio that you've imported.
Instead, it links to that content, saved elsewhere.
All of your video clips will be inside the iMovie Events folder.
When you import a video file into iMovie,
it allows you to add it to an existing Event or create a new Event.
However, unlike video clips,
iMovie will not automatically store audio files or photos anywhere in particular.
If you're using any audio files or photos in your project,
it makes things a lot easier if you copy the files into one of your Event folders
and THEN drag them into iMovie from there.
So, if you're backing up your iMovie project or moving it to another computer,
make sure you copy the project file AND any Event folders you used.
When you're putting these files back onto a computer,
put the project file into the iMovie Projects folder,
and put the Events into the iMovie Events folder.
Once you open or restart iMovie,
you should be able to edit your project just as it was when you left it.