Help · Mac storage

“Your disk is almost full”: what to do.

By Grant and Brad, who make Pangalin's apps · Updated 11 October 2026

That warning is stressful, but it's usually fixable in a few minutes, without deleting anything important. Here's a safe checklist that uses only what's built into macOS (13 Ventura and later).

Before you start: nothing on this list deletes your own documents without you choosing it. If you're unsure about a file, leave it.

The 10-minute checklist

1. See what's using the space. Open System Settings › General › Storage and wait for the coloured bar to finish calculating. It shows the big categories and Apple's own suggestions.
2. Empty the Trash. Files in the Trash still take up space. Open the Trash in the Dock, check there's nothing you want back, then choose Finder › Empty Trash.
3. Clear out Downloads. Open your Downloads folder, choose View › as List and click the Size column so the biggest files are at the top. Old installers (.dmg and .pkg files) are safe to remove once the app is installed.
4. Find your biggest files. In Finder press ⌘F, click the Kind menu, choose Other…, tick File Size, then set it to “is greater than” 1 GB. Old videos, disk images and archives tend to show up here.
5. Remove old iPhone and iPad backups. In Storage, click the ⓘ next to iOS Files. Backups of devices you no longer own can be large; delete only the ones you're sure you don't need.
6. Trim Messages attachments. In Storage, click ⓘ next to Messages to review large attachments, or set Messages › Settings › General › Keep messages to 1 year.
7. Remove apps you don't use. In Storage, click ⓘ next to Applications and sort by size or last opened. Note that deleting an app this way can leave its support files behind; see how to uninstall apps completely.
8. Let Photos keep originals in iCloud. If you use iCloud Photos, turn on Photos › Settings › iCloud › Optimise Mac Storage. Full-size originals stay in iCloud and download when you open them.
9. Restart your Mac. It clears temporary files and lets macOS tidy up. Then check Storage again.

What not to do

• Don't delete things in System or Library folders you don't recognise. Some are needed by macOS or your apps.
• Don't clear caches by hand. Apps rebuild them, so the space comes back only briefly, and deleting the wrong folder can break an app.
• Be wary of “cleaner” apps that report alarming problems. A healthy Mac doesn't need fixing; it needs to know where its space went.

Still full? “System Data” is often the mystery

If a big grey System Data bar is what's left, read what System Data is and what you can safely reduce.