If you have ever checked your Mac's storage settings, you have likely encountered a massive, mysterious category labeled System Data (formerly called 'Other'). This category often consumes dozens, or even hundreds, of gigabytes, leaving users wondering where their space went. This guide provides a comprehensive walkthrough on how to identify and safely remove these files to reclaim your storage.

Step 1: Analyze Your Current Storage Usage

Before deleting anything, you need to confirm how much space System Data is actually taking. Click the Apple Menu () and navigate to System Settings > General > Storage. Wait for the color-coded bar to load. The light-grey section represents System Data, which includes system caches, logs, browser cookies, disk images (.dmg), and local Time Machine snapshots.

Step 2: Clear System and User Caches

Caches are temporary files created by macOS and third-party apps to speed up processes. However, they frequently become bloated. To clear them:

• Open Finder and press Shift + Command + G on your keyboard.
• In the 'Go to Folder' box, type ~/Library/Caches/ and press Enter.
• Review the folders and delete the contents of those you no longer need. Note: It is safer to delete the contents inside the folders rather than the folders themselves.
• Repeat the process for the root library by typing /Library/Caches/ (without the tilde) in the 'Go to Folder' box.

Step 3: Remove Local Time Machine Snapshots

If you have Time Machine enabled, macOS saves 'local snapshots' to your internal drive when your external backup disk is unavailable. This is the #1 cause of sudden System Data spikes. To purge them:

• Open Terminal (Command + Space and type 'Terminal').
• Type the command: tmutil listlocalsnapshots / and press Enter.
• If snapshots appear, type: tmutil thinlocalsnapshots / 10000000000 4 and press Enter. This command instructs the system to reclaim a large portion of the space used by snapshots.

Step 4: Delete Large Log Files

System and application logs record activity for troubleshooting, but they are rarely needed by the average user.

• In Finder, press Shift + Command + G.
• Type ~/Library/Logs and hit Enter.
• Select the files inside these folders and move them to the Trash. This is particularly effective if an app has been crashing repeatedly, as log files can grow exponentially in those cases.

Step 5: Clean Up the 'Application Support' Folder

When you uninstall an app by dragging it to the Trash, it often leaves behind 'residue' in the Application Support folder.

• Go to ~/Library/Application Support using the Go to Folder command.
• Look for folders named after apps you have already deleted and move them to the Trash.
• Pro Tip: Check the MobileSync folder within Application Support. If you have old iPhone or iPad backups, they will be stored here and can be massive.

Step 6: Remove Downloaded Disk Images (.DMG)

Many users download software, install it, and forget to delete the .dmg installer file. These files are categorized under System Data.

• Open Finder and search for .dmg using the search bar.
• Select 'This Mac' as the search location.
• Delete all installer files for programs you have already installed.

Step 7: Empty the Trash and Restart

None of the steps above will actually reclaim your space until you Empty the Trash. Right-click the Trash icon and select Empty Trash. Finally, Restart your Mac. This allows macOS to perform its own background maintenance and update the storage calculation display accurately.

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