“Your disk is almost full” is one of the most common Mac warnings, especially on MacBooks with 256GB of storage. The good news: macOS has everything you need built in. You don’t need a paid “cleaner” app (and many of them do more harm than good).
Step 1: See what's using your space
- Click the Apple menu > System Settings.
- Go to General > Storage.
A coloured bar shows how your storage is split between Applications, Documents, Photos, macOS, System Data and more. Give it a minute to finish calculating.
Below the bar is a list of categories. Click the ⓘ button next to any category to see its biggest files and delete what you don’t need.
Step 2: Use Apple's built-in recommendations
At the top of the Storage page you’ll see Recommendations. Depending on your setup, these may include:
- Store in iCloud — keeps files, photos and messages in iCloud and only downloads them when you need them.
- Optimise Storage — removes Apple TV films and programmes you’ve already watched.
- Empty Bin Automatically (called “Empty Trash Automatically” on US-English Macs) — permanently erases items that have been in the Bin for more than 30 days.
Turn on the ones that suit you. Read each description first — Store in iCloud, for example, relies on having enough iCloud storage.
8 more ways to free up space
1. Empty the Bin
Deleted files aren’t really gone until you empty the Bin. Right-click the Bin in the Dock and choose Empty Bin. (Double-check nothing important is in there first!)
2. Clear out Downloads
Your Downloads folder is often full of old installers (.dmg files), PDFs and zip files. Open Finder > Downloads, switch to List view, and sort by Size to find the biggest offenders.
3. Remove apps you don’t use
In System Settings > General > Storage, click the ⓘ next to Applications. Sort by size or by Last Accessed to spot apps you haven’t opened in months, then select one and click Delete.
4. Find large files
In the Storage settings, the Documents ⓘ view has a Large Files tab — an instant list of everything over a certain size. Old videos and disk images are common culprits.
5. Tidy up Photos
Photos and videos can take up tens of gigabytes. In the Photos app, check the Duplicates album (under Utilities) to merge duplicate photos. Also look at Recently Deleted — photos stay there for up to 30 days and still use space.
6. Delete old iPhone and iPad backups
If you back up your iPhone to your Mac, old backups can be several gigabytes each. Connect your device, select it in the Finder sidebar, click Manage Backups…, and delete any you no longer need. (Keep your most recent one!)
7. Clean up Messages attachments
Years of photos and videos in Messages add up. In Storage settings, click the ⓘ next to Messages to review and delete large attachments. You can also set Messages > Settings > General > Keep messages to 1 year or 30 days.
8. Restart your Mac
Temporary and cache files that build up in System Data are often cleared when you restart. It’s simple, but it can free up a surprising amount.
What about "System Data"?
System Data (called “Other” in older macOS versions) includes caches, logs, temporary files and some app data. It’s normal for it to be fairly large, and macOS manages much of it automatically. Rather than deleting files from system folders manually — which can break things — restart, keep macOS up to date, and remove unused apps.
Wrapping up
Start with System Settings > General > Storage: it shows you exactly where your space has gone and handles most of the cleaning for you. Aim to keep at least 10–15% of your drive free so your Mac stays fast and updates install smoothly.
