I Reduced Mac System Data by 37 GB (No Apps Required), by Let Mike Help on YouTube. 15 min 48 s.
- Video length
- 15 min 48 s
- Time to do it
- 20 minutes
- Difficulty
- Medium
- Steps
- 7
What you need
Steps
Open the Apple menu, choose System Settings, then General and Storage. Wait for the bar to finish calculating, then click System Data to see how much space it takes.
Know what is inside System Data: caches, local Time Machine snapshots, iPhone and iPad backups, and logs. macOS clears most of it on its own, so only step in if you need space now.
Open Terminal from Applications > Utilities. Type tmutil listlocalsnapshots / and press Return to list the local snapshots stored on your startup disk.
Thin those snapshots by typing tmutil thinlocalsnapshots / 21474836480 4 and pressing Return. That asks macOS to free about 20 GB while keeping your most recent snapshots.
For app caches, open Finder, choose Go > Go to Folder, paste ~/Library/Caches and press Return. Sort by size, then move the contents of the largest folders to the Bin.
For old device backups, use Go > Go to Folder again and paste ~/Library/Application Support/MobileSync/Backup. Delete the folders for iPhones or iPads you no longer own or sync.
Go back to System Settings > General > Storage and check the System Data figure again. Restart your Mac if the number has not changed yet.
Tips and common mistakes
Back up your Mac before deleting anything inside Library folders, so a mistake stays reversible.
Clear one app cache folder at a time instead of the whole Caches folder, so you can spot which app misbehaves.
Expect System Data to creep back up, because macOS rebuilds caches and snapshots as you keep working.
Leave folders outside your user Library alone. Those are managed by macOS and are not yours to trim.
Questions
Is it safe to delete System Data on a Mac?
You cannot remove it as a single item. You can clear parts of it, such as local snapshots, app caches and old device backups, and macOS rebuilds whatever it still needs.
Why did System Data grow again after I cleared it?
MacOS keeps caching files, taking new snapshots and writing logs as you use the Mac, so the figure climbs back over days and weeks.
Do I need a cleaner app for this?
No. Terminal, Finder and System Settings cover snapshots, caches and device backups, which are the main parts you can safely reduce.
This guide was drafted from the video's details and general task knowledge. It has not been checked against the full video. Check the video and relevant product instructions before following a procedure. Report a correction.
