
Unfortunately, this is a really common error but it is easily fixed. There are several Mac users in forums all across the web talking about a Disk Space error in iMovie.


If you’re still using up too much disk space, it’s time to think about buying a larger disk or using an external drive. It should be more than enough to use iMovie and anything else you need.

Delete any iPhone backups you no longer need from iTunes.Clean your system cache in /Library/Caches and ~ /Library/Caches.Clear Safari’s cache by selecting Reset Safari from its menu.Select Applications and delete any you no longer need.Check Mail and select Erase Deleted Items and In All Accounts and Mailbox.Check Downloads and delete anything you have downloaded that you no longer need.Empty Trash Automatically is useful if you don’t often delete files by accident while Reduce clutter is okay if you don’t mind Apple deciding what documents are important or not. Optimize Storage is useful if you watch a lot of TV or movies using iTunes. When you select Manage, you have some options.

Presumably, if you’re seeing low disk space messages, you won’t have much available space. You should see a graphical representation of your disk usage where you can see how much storage you have used and how much you have free.
