Mac Disk Usage Analyzer: Read a Treemap and Sunburst

A Mac disk usage analyzer scans your drive and shows which folders hold the space, so you stop guessing. The three common views are the Treemap, the Sunburst and a sorted tree list. Each answers a different question. This guide explains how to read them, what to check first, and what you can do with only the tools built into macOS.

The three views and what each is for

What to look at first

Start with the largest blocks. Most Macs have a handful of folders holding most of the used space. Then check these, roughly in order of how often they turn out to matter:

Check disk usage with Terminal

You do not need extra software to find the biggest folders in your home directory:

du -h -d 1 ~ 2>/dev/null | sort -h | tail -15

Run it again inside the largest folder you find, and repeat. It works, but you read numbers instead of seeing shapes, and each level means a new command.

Why Storage settings is not enough

System Settings → General → Storage groups space into broad categories, and most of the difficult space ends up under System Data. It does not tell you which folder is responsible. For the background, see System Data on Mac. A disk analyzer shows the actual folders instead.

Give the analyzer Full Disk Access

Without Full Disk Access, macOS hides protected folders and some caches from every app, so the map shows less than what is really on the disk. Grant it in System Settings → Privacy & Security → Full Disk Access, then scan again.

Next steps

Once you know where the space is, the fixes are in how to find large files on Mac and how to free up space on Mac.