What is taking up space on my Mac? See it on a disk map

Why your Mac's storage fills up without you noticing

System Settings tells you how full your disk is and splits it into a few broad bars, such as Applications, Documents and System Data. It doesn't tell you which folder grew. Finder can show folder sizes, but only one folder at a time, and only after it has measured each one.

Space usually goes in places you don't look: a folder of old project exports, a Downloads folder no one has sorted in years, a virtual machine, an app's data in your Library folder, a music or video library that moved to this Mac with a migration. A treemap shows all of it at once, so the largest things are simply the largest blocks on screen.

How to see what is using your Mac's storage

Choose Home Folder or Whole Disk and press Scan. Tidy My Mac measures every folder below it and draws the map. The scope you picked is remembered for next time.

• Double-click a folder's block to open it, and keep going down until you reach the files.
• The path along the top takes you back to any folder above, and ⌘↑ goes up one level.
• A list beside the map shows the same items, largest first, with their size and their share of the folder.
• Blocks are coloured by kind, with a key below the map: folders, apps and bundles, video, audio, images, archives and disk images, documents, and code and data.

Items too small to matter, under 1 MB or under half a percent of their folder, are grouped into one block per folder, so the map stays readable while every total still counts every byte. Apps and other bundles appear as one block with their full size, and a file with several hard links is counted once.

Home folder or whole disk

Home Folder is where your own files are, and where almost all the space you can free lives. Whole Disk maps everything from the top of the startup disk, including Applications and macOS's own folders. Other disks are left out.

A whole-disk map also sets what it found against how much of the disk is used. The difference is mostly macOS itself, local Time Machine snapshots, purgeable space and folders your account can't read. That is a large part of what System Settings calls System Data. If some folders couldn't be read, the map says how many, so you know its totals are lower than they should be.

Preview, reveal, or move to the Trash

Select a block to see its full path, size and share of its folder. Show in Finder and Move to Trash sit right below the map, and right-clicking a block also lets you Open it, Quick Look it or Copy Path. When something goes to the Trash, its block disappears and every folder above it shrinks to match, without rescanning.

One scan feeds the whole Clean up group

The scan that builds the map also fills Large Files, Duplicates and the Junk Cleaner, so after one pass over your disk each of them already has its results. If the map shows a folder full of caches or logs, the Junk Cleaner is the safer way to clear it, because it knows which of those files are safe to remove.

What stays on your Mac

Disk Map reads folder and file names and sizes. It doesn't open your files, and nothing it measures is sent anywhere. The Privacy Policy lists every request the app makes.

Full Disk Access

Without Full Disk Access, the map leaves out Desktop, Documents and Downloads, which macOS protects with a prompt for each folder, and some folders in your Library can't be read. Grant it once, at first launch or from the banner in the app, for a complete map. You can revoke it at any time in System Settings → Privacy & Security → Full Disk Access.