Ask Max: What is a Start Up Disk?
I'm trying to download a movie from iTunes but I keep getting a message that my startup disk is full and that I should delete files to create room.
What is a startup disk?
The startup disk is the drive that your operating system is installed on and is used to house your applications and home folders. For most users, it's the Macintosh HD.
The reason you're receiving the notice, is due to the fact that your computer requires a certain percentage of free space on that drive in order to function reliably. Ideally, you should have space greater than 10% available. To check the available space on your drive, right-click the Macintosh HD on your desktop and choose "Get Info." In the Info window, you'll see the capacity (total capacity), available (available capacity), and used (capacity used) for your startup disk.
In older OS X versions like Snow Leopard (10.6.8) and others, try this:
Select your startup disk drive (Macintosh HD for most users)
Press 'command' & 'i' keyboard combination to show the Info window described above.
Easy ways to free up space are to empty the trash and uninstall unused applications. Also, in most cases, media files are often the biggest consumers of drive space so it might be a good idea to move large media files (movies, music, & images) to a separate external drive like this 3TB Hi-Speed Thunderbolth and USB 3.0 from LaCie. Doing this should free up the space you need.