iMovie '11: Duplicate a project
Duplicating a project is useful if you want to edit the project but retain a copy of the original version.
To duplicate a project:
In the Project Library, click to select the project you want to duplicate, and then choose File > Duplicate Project.
The File menu appears in a light gray bar across the top of your computer screen.
A new project is created and is listed above the original project. It has the same filename as the original, appended with a number.
Double-click the name and type a new one, if you want.