How to Free Up Disk Space on Mac: 10 Steps That Actually Work

July 2026 · 8 min read · Dev Box Cleaner

"Your disk is almost full." You've deleted a few videos, emptied the Trash, and somehow macOS still shows a mysterious, enormous System Data wedge. This guide is the practical version: ten steps, ordered by effort-to-payoff, that reliably free real gigabytes.

1. Look before you delete

Guessing is how people spend an hour deleting photos to gain 2 GB while a 60 GB folder of old iOS simulator files sits untouched. Start by seeing the disk: a treemap tool maps every folder as a size-proportional block, so the real space hogs are obvious in seconds. (Apple's built-in Storage settings only shows coarse categories — it hides exactly the stuff this list targets.)

2. Empty the Trash — including hidden ones

Files in the Trash still occupy disk. Also check per-drive trashes on external disks and the hidden mail/photos trashes: Photos → Recently Deleted keeps everything for 30 days.

3. Triage your Downloads folder

Downloads is where disk space goes to die: installers (.dmg/.pkg) you'll never run again, zip files you already extracted, PDFs from 2023. Sort by size and by date; anything older than a year that you haven't opened is a safe delete.

4. Clear app and user caches

du -sh ~/Library/Caches/* | sort -rh | head -15

Browsers, Spotify, Slack, Teams and design tools happily cache many gigabytes. Caches regenerate — clearing them is safe. Keep expectations realistic: apps rebuild what they actively use, so measure the win after a few days, not immediately.

5. Delete Time Machine local snapshots

When your backup disk isn't connected, macOS keeps hourly snapshots on the internal disk — a classic source of "invisible" System Data:

tmutil listlocalsnapshots /
# free most of it in one move:
tmutil thinlocalsnapshots / 999999999999 4

6. Remove old iPhone/iPad backups

Local device backups are often 5–20 GB each: Finder → [your device] → Manage Backups, or look in ~/Library/Application Support/MobileSync/Backup. Delete backups of devices you no longer own.

7. Hunt the single biggest files

A handful of forgotten giants — an old VM image, a raw video export, a macOS installer — often beats a thousand small deletions. Find your top 100 files by size and judge each one; ten minutes well spent.

8. Developer? Your tools are hoarding

Xcode's DerivedData, Archives and iOS DeviceSupport, plus node_modules and package manager caches, commonly hide 50–100 GB on a dev Mac. We wrote dedicated guides: clearing DerivedData, Archives & DeviceSupport and node_modules & package caches.

9. Uninstall apps properly

Dragging an app to the Trash leaves its data in ~/Library/Application Support, ~/Library/Caches and ~/Library/Containers. After uninstalling something big (games, DAWs, IDEs), check those folders for leftovers bearing the app's name.

10. Make it a habit, not a crisis

Everything above grows back — caches, snapshots, downloads, dev junk. The difference between a chronically full disk and a healthy one is a monthly ten-minute sweep with a tool that shows you what changed.