“Your disk is almost full” on Mac: what to do first

When macOS says “Your disk is almost full”, it means your startup disk is close to running out of room. Act soon: with little free space, macOS can't write the files it needs to run smoothly, and updates won't install. Here is what to do in the first ten minutes, in the order that frees the most space for the least effort.

Do these five things first

1. Empty the Trash. Choose Finder → Empty Trash. Files you deleted still use space until you do.
2. Delete big downloads. Open the Downloads folder, switch to list view and sort by Size. Old videos, disk images (.dmg) and installers (.pkg) are usually the biggest items. See whether it is safe to delete .dmg and .pkg files.
3. Restart your Mac. A restart clears temporary and swap files, which can free several gigabytes on a Mac that has been running for days.
4. Check what is using the space. Open System Settings → General → Storage and look at the biggest slice of the bar. Each category has an ⓘ button that lists its files.
5. Remove old iPhone or iPad backups. In Storage, click the ⓘ next to iOS Files. One old backup can be larger than everything else you just deleted. See how to delete old iPhone backups.

If the biggest slice is System Data

System Data holds caches, logs, Time Machine local snapshots and developer files. It is often the biggest slice and the hardest to read. Our guide on how to clear System Data explains what inside it is safe to remove, and how to delete Time Machine local snapshots covers the part that is easiest to get back.

What not to do in a hurry

• Don't delete folders in /System, /Library or your whole ~/Library folder.
• Don't delete files from inside your Photos library package. Delete photos in the Photos app, then empty its Recently Deleted album.
• Don't run Terminal commands you found online unless you understand them. rm -rf has no undo.

Stop the warning coming back

• In Storage, turn on Empty Trash Automatically.
• Delete installers once an app is installed.
• Keep 10 to 15 percent of the disk free, and check the Storage screen once a month.
• Work through the longer list in how to free up space on a Mac when you have half an hour.

The fast way with Roomy

Roomy scans your Mac in seconds and shows how much space you can free and where it is, with caches, logs, old installers, backups and developer data in one list. Only rebuildable items such as caches are selected for you, so you can click Clean Safe Items without second-guessing, then review the rest at your own pace.

Frequently asked questions