How to Clear or Reduce System Storage on Mac

If your Mac is running low on space, the System Data (or System) category in Storage settings can quietly eat dozens of gigabytes. This guide walks you through the most effective ways to clear or reduce that storage, from simple built-in tools to more advanced cleanup steps. You won’t need any third-party software, and you can do everything with the tools already on your Mac.

What You’ll Need

• Your Mac’s administrator password (for some steps)
• About 30–60 minutes of time
• An external drive or cloud service if you plan to move large files

Step-by-Step

1. Check what’s taking up space. Click the Apple menu  > System Settings (or System Preferences on older macOS) > General > Storage. Wait a moment for the bar to load. It shows categories like Applications, Documents, and System Data. Note the size of System Data – that’s your main target.
2. Use the built-in Storage Management tools. In the same Storage screen, click the “i” button next to each category. For Documents, you’ll see options like “Large Files,” “Downloads,” and “File Browser.” Delete any files you no longer need. This often clears the most space quickly.
3. Empty the Trash. After deleting files, right-click the Trash icon in the Dock and choose “Empty Trash.” This permanently removes files and frees up space immediately.
4. Clear caches and temporary files. Open Finder, press Command + Shift + G, and type ~/Library/Caches. You’ll see folders for each app. You can delete the contents of these folders (but not the folders themselves). Be careful: only delete caches for apps you recognize. This is safe for most apps – they’ll recreate the caches as needed.
5. Remove old iOS backups and device backups. If you back up an iPhone or iPad to your Mac, those backups can be huge. Go to Finder and click your device under Locations (if connected), then manage backups. Or go to ~/Library/Application Support/MobileSync/Backup and delete old backup folders you no longer need.
6. Clean up Time Machine local snapshots. If you use Time Machine, your Mac may keep local snapshots that count as System Data. To see them, open Terminal and run tmutil listlocalsnapshots /. To delete them, run tmutil deletelocalsnapshots followed by the snapshot date (e.g., 2025-04-01-123456). This can free up significant space.
7. Delete old log files and crash reports. In Finder, go to ~/Library/Logs and /Library/Logs. Look for large log files or folders with old crash reports. You can delete them – they’re not needed for daily use.
8. Remove unused apps and their leftover files. Drag unused apps from the Applications folder to the Trash. Then check ~/Library/Application Support and ~/Library/Preferences for folders related to those apps and delete them. This prevents leftover data from counting as System Data.
9. Restart your Mac. Sometimes System Data is just temporary files that macOS will clean up on its own. A simple restart can clear hundreds of megabytes or more.
10. Use the “Optimize Storage” features. In the Storage settings, enable “Optimize Storage” to automatically remove watched movies and TV shows, and “Empty Trash Automatically” to remove items older than 30 days. Also consider “Reduce Clutter” – it suggests old files to delete.

Common Mistakes

• Deleting the wrong caches. Avoid deleting caches for apps that are currently running (like your browser) – you might lose unsaved state. Quit apps first.
• Using third-party “cleaner” apps that promise to delete “System” files. Many of these are not necessary and can remove important files. Stick to the built-in methods.
• Forgetting to empty the Trash. Files you delete are still taking up space until you empty the Trash.
• Deleting files in ~/Library without knowing what they are. Some folders (like Application Support) contain essential data. Only delete folders you are sure are safe.
• Ignoring the “Other” or “System” category. It’s not always a single thing – it’s a mix of caches, logs, and temporary files. You need to tackle each source separately.

Tips

• Use the “Large Files” view. In Storage settings > Documents, sort by size and delete the biggest files first – it’s the fastest way to free up space.
• Move files to external storage or iCloud. If you have large video or photo libraries, consider moving them to an external drive or enabling iCloud Photos with “Optimize Mac Storage.”
• Clear browser caches. In Safari, go to Settings > Privacy > Manage Website Data and remove old data. In Chrome, go to Settings > Privacy and security > Clear browsing data. This can free up several gigabytes.
• Check your Downloads folder. It’s easy to accumulate old installers and disk images (.dmg) that are no longer needed. Delete them.
• Run a disk check. Use Disk Utility > First Aid to repair permissions and file system issues, which can sometimes reduce system storage.
• Consider a fresh start. If System Data is still huge after all this, you might want to back up your files and reinstall macOS. This is a last resort but can wipe out years of accumulated junk.

Troubleshooting

• System Data is still huge after following all steps. This could mean there are large files you haven’t found. Use a free tool like OmniDiskSweeper or GrandPerspective (but note: these are third-party apps) to visualize where space is going. Or use the Terminal command du -sh ~/Library/* to see which subfolder is largest.
• You can’t delete a cache file because it’s “in use.” Quit the associated app, then try again. If it still fails, restart your Mac and try again.
• You accidentally deleted an important file. If you haven’t emptied the Trash, you can restore it. If you have, try a Time Machine backup to restore the file.
• Storage bar doesn’t update after deleting files. Wait a few minutes – macOS recalculates storage usage periodically. You can also restart your Mac to force a refresh.
• Your Mac is running slowly after cleanup. Some apps may take longer to load the first time after their caches are cleared. This is normal and should improve after a few uses.

Frequently Asked Questions

What exactly is “System Data” on a Mac?

System Data (called “Other” on older macOS versions) is a catch-all category for files that don’t fit into the main categories like Apps, Documents, or Photos. It includes caches, logs, temporary files, Time Machine local snapshots, and sometimes old iOS backups.

Is it safe to delete files in the Library folder?

Mostly yes, but only if you know what you’re deleting. The ~/Library/Caches folder is safe to empty, but avoid deleting folders like Application Support unless you’re sure they’re not needed. When in doubt, leave it.

How often should I clean system storage?

There’s no set schedule. If you regularly download large files or use video editing software, you might need to clean every few months. Otherwise, once or twice a year is usually enough.

Will clearing caches slow down my Mac?

No, not permanently. Caches are meant to speed up apps, but they’re rebuilt as you use the apps again. You might notice a slight delay the first time you open an app after clearing its cache, but it’s temporary.

Can I move System Data to an external drive?

No, System Data is made up of files that macOS needs to run. You can’t move it, but you can reduce it by following the steps above.

Why did my System Data suddenly grow after an update?

macOS updates often create temporary files and caches that are later cleaned up. It’s normal for System Data to grow temporarily after an update. If it stays large for weeks, try restarting your Mac or following the cleanup steps.

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