If I don’t know what it is, and the system doesn’t seem to know either, then why can’t I just delete those files? When that happens, I think most of us tend to look at the Other category and think, there’s a lot of space being used by Other. That’s a common question, one you may often ask yourself, especially when you need to free up space when your drive starts to fill up. Purgeable space is more or less unique to the Mac you can find out more about it in the Rocket Yard Guide: What is Purgeable Space in macOS? The next category that seems to get a lot of attention is Other. (The Other category, shown here in gray, shows my startup drive (Casey) with a small percentage of Other files, while my data drive (Casey Cat) contains nothing but Other file types.) The categories change as new versions of the OS are released, but the current categories include System files, Documents, Apps, iTunes, Backups, Other, Audio, Music Creation, Photos, Movies, and Purgeable space. Mouse over a color bar, and a text balloon will pop up, telling you what the category is and how much disk space it’s using.

If you’re not sure how to find the categories, click the Apple logo in the menu bar in the Finder, select About This Mac from the dropdown menu, and then click the Storage tab. Originally introduced in OS X Lion as part of a feature upgrade to the System Information app, the Storage tab displays how much free space is available on each disk attached to your Mac, as well as how a disk’s storage is being used, by category. One of the niceties in the Mac OS is the ability of the system to display how your storage space is being used.

Mac hard drive space color