If you have ever checked your Mac's storage settings, you have likely encountered a mysterious, large category labeled System Data (formerly known as 'Other'). This category often consumes dozens or even hundreds of gigabytes, leaving you with no room for new files or software updates. In this guide, we will walk you through the most effective ways to reclaim your storage by safely deleting hidden junk.

1. Identify Your Storage Distribution

Before deleting anything, you must confirm how much space System Data is actually using. Click the Apple Menu (), select System Settings, navigate to General, and then click Storage. Wait for the graph to load. If the grey 'System Data' bar is significantly larger than your Documents or Applications, you need to perform a manual cleanup.

2. Clear Out User Cache Files

Your Mac stores temporary files for every application you use. While these are meant to speed up performance, they often fail to delete themselves, leading to massive bloat. To clear them:

• Open Finder and press Command + Shift + G on your keyboard.
• In the 'Go to Folder' box, type ~/Library/Caches/ and hit Enter.
• Navigate through the folders and delete the contents of folders belonging to apps you no longer use. Note: Avoid deleting the folders themselves; only delete the files inside.
• Repeat the process for the system-level cache at /Library/Caches/ (without the tilde).

3. Delete Local Time Machine Snapshots

If you use Time Machine, macOS often creates local snapshots on your internal drive when your external backup drive is disconnected. These are stored under System Data. To remove them:

• Open Terminal (Command + Space and type 'Terminal').
• Type tmutil listlocalsnapshots / and press Enter to see a list of snapshots.
• To delete them, type tmutil deletelocalsnapshots [date] where [date] is the string of numbers provided in the list. This can immediately free up gigabytes of space.

4. Remove Old iOS and iPadOS Backups

If you have ever backed up an iPhone or iPad to your Mac, those backup files are tucked away in the System Data category.

• Go to System Settings > General > Storage.
• Scroll down until you find iOS Devices and click the 'i' icon next to it.
• Select any old backups for devices you no longer own and click Delete.

5. Clean Up the Application Support Folder

When you drag an app to the Trash, its support files often stay behind in a hidden directory. To find them:

• In Finder, press Command + Shift + G and type ~/Library/Application Support/.
• Look for folders named after apps you have already uninstalled. Right-click these folders and select Move to Trash.

6. Clear Out Logs and Download Folders

System logs and forgotten files in your Downloads folder are common culprits for storage bloat.

• Navigate to ~/Library/Logs/ and delete old log files from third-party applications.
• Check your Downloads folder and sort by Size. Delete any large .dmg or .pkg installers that you have already used to install software.

Pro Tip: After completing these steps, always remember to Empty your Trash. macOS does not reclaim the disk space until the Trash is completely purged.

💡 Pro Tip: Keep your software updated to avoid these issues in the future.