iLife Tutorial: Organise files on multiple hard drives in iMovie

Rewind a few years and most camcorders captured footage onto tape-based formats like MiniDV. When you wanted to edit the footage, you copied the best bits to your Mac, and the outtakes stayed on tape. Camcorders were often only dusted off to shoot special occasions, and this kept your Mac’s hard drive relatively free of video clips.
In these digital days we carry a video- recording iPhone with us at all times, so we’re more likely to shoot everyday events. To free up space on our iPhone we need to download clips onto our Mac, and we therefore have much more footage to store. Other gadgets like digital SLR cameras produce huge HD video files that fill our poor Mac’s hard drive.
You can solve your storage problem by buying an external hard drive. iMovie enables you to store and manage clips on external drives, so you can free up the Mac’s disk space.

1: Attach external hard drive
Plug in an external hard drive. For it to work with iMovie you’ll need to format it as a Mac OS Extended disk. You can partition it as several disks and dedicate one of them to storing your iMovie Projects and Events.

2: Group by Disk
Open iMovie. By default video footage is stored on your Mac’s hard disk in the Event Library. Go to the Event Library panel. Click on the ‘Group Events by Disk’ icon. You’ll now see any attached hard drives appear.

3: Move an Event
To move clips from the Macintosh HD to an external disk, hold the Command key and drag the relevant Event to the external disk’s icon. The Event will appear under the relevant disk.

4: Copy Projects
If you want to edit existing Projects using iMovie on another Mac, drag it from the Edit Project window onto an external hard drive. You’ll be given the option of transferring any relevant Event clips at the same time.