You can give your Mac hard drive come breathing room by relocating iMovie footage to an external firewire hard drive.
When you first started using your shiny new Mac, you thought the hard drive was so large you would never run out of storage. Then you started using iMovie for video, and now your Mac hard drive is almost full. Fortunately, you can free up lots of space on your Mac hard drive by moving iMovie video footage to an external hard drive. Dragging the video files in Finder will not work – doing this properly is a two-step process.
First, you must prepare your new external hard drive to hold video files in a format (Mac OSX Extended – Journaled) that iMovie likes. To do this, connect your new external hard drive to the Mac. It should show up as an appropriately named icon on the Desktop. Make note of its name so you can recognize it. Bring up the Disk Utility and look at the list of drives. Identify the external drive, and click on the drive. Don’t click on any partitions underneath the drive, click on the entire drive. Then select Partitions, a Volume Scheme of 1 Partition, make up a name for the volume, pick a format of Mac OSX Extended – Journaled, and click Apply.
Your Mac will take a few minutes while it removes all existing information from the external hard drive.
Now that the external drive is in a format that iMovie likes, whenever you import new video footage you can select your external drive in the Save To dropdown box. You can also move your existing footage from the Macintosh hard drive to the external hard drive. Just bring up iMovie and select Events by Volume in the view menu. Then drag an event from its current location to the external drive:
Each event takes a few minutes to move. Rinse and repeat!