If you have ever checked the storage settings on your Mac, you have likely encountered a mysterious, massive category labeled System Data (formerly known as "Other"). This category can often consume hundreds of gigabytes, leaving you with little room for your own files. While macOS manages this automatically to some extent, it often fails to purge unnecessary files.

This guide will show you how to identify and delete the hidden files cluttering your System Data to reclaim your disk space.

Step 1: Identify What is Taking Up Space

Before deleting files, you need to see the current state of your storage. Go to the Apple Menu > System Settings > General > Storage. Wait for the graph to calculate. Hover over the dark grey section to confirm the size of your System Data. If it exceeds 50GB-100GB, it is time for a manual cleanup.

Step 2: Clear Local Time Machine Snapshots

One of the biggest culprits behind bloated System Data is Local Snapshots. If you use Time Machine, macOS saves backup snapshots to your internal drive when your external backup disk isn't connected.

• Open Terminal (Command + Space and type "Terminal").
• Type the following command and hit Enter: tmutil listlocalsnapshots /
• If you see a list of dates, you have local snapshots. To delete them, type: tmutil deletelocalsnapshots [date] (replace [date] with the specific string from the list).
• Alternatively, turning Time Machine Off and then On again in System Settings often clears these automatically.

Step 3: Manually Clean the Library Caches

Your Mac stores temporary files for applications in the Caches folder. Over time, these files can grow significantly, especially for media editing or web browsing apps.

• Open Finder.
• Press Shift + Command + G to open the "Go to Folder" window.
• Type ~/Library/Caches and hit Enter.
• Look through the folders and move the contents of large folders to the Trash. Note: Do not delete the folders themselves, only the files inside.
• Repeat the process for the root library by typing /Library/Caches in the "Go to Folder" window.

Step 4: Remove Old iOS Backups

If you have ever backed up an iPhone or iPad to your Mac, those backups are stored within the System Data category. These files are often 30GB+ each.

• Connect your device or open Finder.
• In the sidebar, select your iPhone/iPad.
• Under the General tab, click Manage Backups....
• Select old backups you no longer need and click Delete Backup.

Step 5: Clear Out Application Support Files

Even after you uninstall an app, its support files often stay behind in your Library. These are categorized as System Data.

• In Finder, press Shift + Command + G.
• Go to ~/Library/Application Support.
• Identify folders belonging to apps you have already uninstalled and move them to the Trash.

Step 6: Empty the Trash and Restart

Storage calculations in macOS often don't update in real-time. After performing the steps above, Empty your Trash. Then, Restart your Mac. This forces the operating system to re-index the file system and will reflect the newly available space in your Storage settings.

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