How do you move iMovie projects and events on a Mac to an external hard drive to save space

Hi,

Assuming that you are talking about iMovie 9, take a look at my post in this thread explaining how to move your iMovie 9 projects and events folders to an external drive:

how to move/copy/transfer iMovie projects to new computerhow to move/copy/transfer iMovie projects to new computer

If you are referring to moving iMovie 10 projects to an external drive, you would need to open the Movies folder on your Mac, select and Edit/Copy the iMovie Library folder that you want to move, and then Edit/Paste the library to an external drive that has been formatted Mac OS Extended (Journaled). Here's a link to the online Help menu that explains it:

https://help.apple.com/imovie/mac/10.1/#/mov3fa25bae7