How to clear System Data on Mac, step by step

Clearing System Data safely comes down to one rule: know what a folder is before you remove it. Follow these steps in order. The first ones are the safest and usually free the most space.

Before you start

• Have a recent backup. Time Machine is fine.
• Check the starting number: System Settings › General › Storage. Wait for it to finish calculating.
• Quit the apps whose files you're going to clear.

Step 1: See what's actually in yours

System Data is different on every Mac. In Finder, choose Go › Go to Folder…, enter ~/Library, switch to list view, then choose View › Show View Options and turn on Calculate all sizes. Sort by Size. The biggest folders are where to look first. Usually it's Application Support, Caches, Developer or Containers.

Macaroom does this step for you: it names each big item and says whether it's safe to clear.

Step 2: Delete old iPhone and iPad backups

Often the easiest big win. Connect the device, select it in Finder's sidebar, click Manage Backups…, and delete backups of devices you no longer own, or older copies. Keep a device's only backup. Full guide.

Step 3: Clear app caches

Open ~/Library/Caches, sort by size, and move the folders of big apps you've quit to the Trash. Leave folders starting with com.apple. alone. Many apps, such as browsers, Spotify and Slack, also have a clear-cache button in their settings, which is the cleanest way. Full guide.

Step 4: Clean up app data inside the app

Messages, Mail, WhatsApp, Telegram, Slack and similar apps can hold many gigabytes of attachments. Don't delete their folders. Use the app:

• Messages: Settings › General › Keep messages: 1 year or 30 days.
• Mail: delete large attachments, then Mailbox › Erase Deleted Items.
• Other chat apps: look for Storage or Data in their settings.

Step 5: If you're a developer

Developer tools are often the biggest part of System Data:

• Xcode DerivedData: safe to delete.
• iOS DeviceSupport: old versions are safe to delete.
• Simulators: run xcrun simctl delete unavailable.
• Docker: run docker system prune.
• Package caches: npm cache clean --force, brew cleanup.

Step 6: Restart, then empty the Trash

A restart clears some temporary files. Emptying the Trash actually frees the space. Then check Storage settings again. It can take a few minutes to update.

What to leave alone

Leave it	Why
/System and /Library	macOS needs them. Deleting files here can stop your Mac starting up.
Time Machine local snapshots	macOS removes them by itself when space runs low.
Swap and sleep files	macOS creates and removes them as it runs.
Folders you don't recognise	If you can't say what it is, don't delete it.

Questions people ask

How long does it take to clear System Data?

Most of the steps take a few minutes each. The slow part is finding what's big. Once you know, deleting old backups and caches is quick.

Is there a Terminal command to clear System Data?

There's no single safe command, because System Data is many different things. Commands like rm -rf on whole folders delete permanently and can break apps. Use the step for each item instead.

Will clearing System Data delete my files?

Not if you follow these steps. Your documents, photos and music aren't in System Data. The risky part is app data, which is why step 4 cleans it from inside each app.

Related guides

• System Data taking 100 GB or more? Here's why
• Mac storage full? Where the space really went
• What happened to Other storage on Mac?