How to free up space on a Mac: what to delete first

Before you delete anything, look at where the space went

Open the Apple menu, choose System Settings, then General, then Storage. The bar shows how your disk is divided, and most rows have an info button that lists the files behind them. Two minutes here tells you which of the steps below are worth your time.

If you are comfortable in Terminal, this command lists the folders in your home folder by size. It only reads sizes. macOS may ask for permission to look inside Documents, Desktop or Downloads.

du -sh ~/* 2>/dev/null | sort -h

1 to 3: Trash, downloads and forgotten big files

These three are the quickest wins, and the only thing at risk is a file you forgot you wanted.

• Empty the Trash. Files in the Trash still take up space. Right-click the Trash in the Dock and choose Empty Trash. What you lose: the chance to put those files back, so glance through it first. Photos has its own Recently Deleted album, which holds items for 30 days unless you empty it too.
• Old downloads and installers. Open ~/Downloads and sort by size, then by date. Disk images (.dmg), installer packages (.pkg) and zip files you have already opened are safe to remove: the app is installed, and the installer can be downloaded again. What you lose: nothing you cannot fetch again, as long as the source still exists.
• Big files you forgot. In Storage, click the info button next to Documents and open Large Files. Old screen recordings, exported videos, virtual machine images and duplicate archives tend to show up here. What you lose: whatever you delete, permanently, once the Trash is emptied. Move anything you might need to an external drive instead.

4 and 5: App caches and unused apps

App caches live in ~/Library/Caches. Browsers, music and chat apps and design tools keep the largest ones. To clear them, quit the app, choose Go then Go to Folder in Finder, enter ~/Library/Caches, and move the contents of the large folders to the Trash. What you lose: nothing permanent. Apps rebuild their caches, so the first launch and the first page loads are slower, and some of the space comes back over time.

Unused apps are found in Storage under Applications, where you can sort by size and by when each app was last used. Dragging an app to the Trash removes the app itself, but its support files, caches and preferences stay in your Library. For a large app those leftovers can be bigger than the app. What you lose: the app, and its local data if you remove the leftovers too. Check that anything you need is exported or synced first.

6: iPhone and iPad backups

If you have ever backed up an iPhone or iPad to this Mac, the backups are in ~/Library/Application Support/MobileSync/Backup. Each one can be as large as the data on the device, and backups of phones you no longer own are never removed automatically.

To delete them, open Storage and click the info button next to iOS Files, or connect the device, select it in the Finder sidebar and click Manage Backups. Do not delete the folders by hand. What you lose: the ability to restore that device from that backup. Keep the most recent one for any device you still use, unless it also backs up to iCloud.

7: Developer junk, if you write code

On a developer's Mac this step often frees more than all the others together. Most of it is build output and download caches that tools recreate on demand.

• Xcode: ~/Library/Developer/Xcode/DerivedData is build output and is safe to delete. Old simulators go with xcrun simctl delete unavailable.
• JavaScript: node_modules folders inside old projects. Running the install command again restores them.
• Package managers: npm, Yarn, pnpm, pip, CocoaPods and Cargo all keep download caches. For Homebrew, the command below removes old versions and stale downloads.
• Docker: its disk image keeps its size after you delete containers. Remove unused images and volumes from Docker Desktop.
• What you lose: time. The next build or install has to download and compile again.

brew cleanup

8 and 9: Local snapshots, photos and message attachments

Local snapshots are copies Time Machine keeps on your startup disk between backups. They can hold on to space from files you have just deleted, which is why free space sometimes does not rise straight away. They expire after about 24 hours and macOS removes them sooner when it needs room, so the usual fix is to wait. You can list them with tmutil listlocalsnapshots / in Terminal.

Photos: if you use iCloud Photos, open Photos, choose Settings, then iCloud, and turn on Optimize Mac Storage. Full-size originals stay in iCloud and smaller versions stay on the Mac. What you lose: offline access to originals. Without iCloud Photos, the only options are deleting photos or moving the library to an external drive.

Message attachments: every photo and video sent to you in Messages is stored in ~/Library/Messages. In Storage, click the info button next to Messages to see attachments by size and delete the large ones. What you lose: those attachments, and with Messages in iCloud turned on they are removed from your other devices too.

Doing the same thing with Diskzy

Diskzy is a native Mac app that maps the whole disk and lets you search files by name, kind, size or age, which covers the forgotten big files step. Its Clean up tab finds caches, logs, Xcode leftovers, project build folders, package manager caches and old installers. Each item is ticked or unticked with a reason, and apps that are open are left alone. Its Uninstall tab removes an app together with what it left behind.

Everything it removes goes to the Trash, so nothing is gone until you empty the Trash. It is free for 72 hours with everything unlocked, then $9 once for 2 Macs, with no subscription.