Collaboration

Unfortunately, it is not easy to collaborate in editing an iMovie project with others who are using different Macs or devices. You can collaborate between Macs by physically transferring (such as with a thumb drive) the iMovie library that contains the project from one Mac to another. Each Mac must be using the same exact version of iMovie that was used to create the project. The thumb drive must be formatted Mac OS Extended (Journaled) or APFS. One cannot collaborate at all between Macs and other divices like iPad and iPhone.

Before transferring the library and project, first click on the library's name in the media sidebar and do a File/Consolidate Library Media. Then go to the projects browser (where your projects are displayed as icons) and select the project by clicking on it. Then do a File/Consolidate Project Media. Those procedures will insure that all media used in the project will carry over with it when you transfer it back and forth.

You can also transfer the exported standalone movie back and forth by thumb drive or email or AirDrop, import the movie into an iMovie project, and do some limited editing. (Again, the iMovie version must be exactly the same as the one used to create the project.) The movie would be one long clip that could be split, trimmed, delete segments, add effects, add other clips, ect. Previously embedded clips could not be changed or edited for the most part, unless you could delete the previously edited portion and reimport the original source clip.

-- Rich