System / Other on macOS is basically a junk drawer with a PR team, so yeah, it gets ugly fast. @ombrasilente already nailed most of the obvious and semi-advanced stuff, so I’ll skip repeating that laundry list and hit a few angles they didn’t.
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Kill local “Downloads” clones in apps
Some apps quietly keep their own giant downloads folder. Check:
• Zoom: Settings > Recording > open folder, plus “Virtual Backgrounds” in ~/Library/Application Support/zoom.us
• WhatsApp / Telegram / Signal desktop: each has its own “Media” folder under Application Support
• Microsoft Teams / Slack: also stash caches and media separately from your main Downloads -
Check for multiple photo / media libraries
Even if you use Photos, you might have:
• Old iPhoto / Aperture libraries still lying around (search in Finder for*.photolibrary,*.photoslibrary,*.aplibrary)
• “Final Cut Pro / Premiere / DaVinci” projects with render caches & proxy media in Movies or Documents
These can easily be 20–100 GB. If they’re for old projects, move them to an external drive, don’t just hope Photos “optimized” everything. -
Look for third‑party backup & sync clutter
Everyone talks about Time Machine, but:
• Dropbox / OneDrive / Google Drive can all store offline copies of everything
– Check each app’s settings and set large folders to “online only” or equivalent
• Old backup apps (Carbon Copy Cloner, SuperDuper, some game launchers) may have outdated backups in/Users/Sharedor/Volumesclones sitting on your internal disk -
Virtualization & dev tools are silent killers
If you’ve ever “just tested” something:
• Parallels / VMware / UTM:
– Their VM images are often in~/Documentsor~/Parallelsand can be 30–80 GB each
• Docker: even worse
– Install Docker Desktop, then Preferences > Resources > Disk > Clean / Prune
– Or in Terminal:docker system dfanddocker system prune(careful: removes unused stuff)
These typically register as “System Data” / “Other” and look completely mysterious. -
Log files & diagnostic dumps
Not glamorous, but sometimes huge:
• Go to/var/logand~/Library/Logs
Do not delete everything blindly, but large.logor.traceor.spinfiles from apps you do not care about can go. Usually safe if they’re clearly for an app you’ve uninstalled. -
Old user accounts and shared folders
This one contradicts what some people suggest: I would not immediately start nuking caches before checking for old user accounts. Caches rebuild, but a forgotten user account can be holding your actual missing 80 GB.
• System Settings > Users & Groups
– If you see old accounts you truly do not use: delete and choose “Delete the home folder”. That’s often the biggest single win. -
Don’t blindly trust the “System Data” number
macOS is… optimistic. It mislabels things and sometimes does not update the bar graph in real time. If it says “System” is 200 GB but Finder’s “Get Info” on your whole disk shows a lot less used, then:
• Boot into Safe Mode (hold Shift on Intel, or press and hold power on Apple Silicon > Continue in safe mode)
Use the Mac a bit, then restart normally. Safe Mode triggers extra cleanup and can cause System Data to recalc more accurately. -
Set a “maintenance floor” so this doesn’t keep happening
What finally stopped my Mac from turning into a digital hoarder:
• Decide on a minimum free space like 20–30 GB
• Once a month:
– Sort your home folder by size in Finder
– Check Downloads, Movies, and any “Projects” folder
– Review at least one “Library/Application Support” folder for apps you no longer use
It’s annoying, but much less annoying than “0 bytes free” and random glitching while you’re trying to edit a doc.
If after all that the System / Other bar still looks insane, that’s often a sign of a messed-up APFS snapshot or a half-broken system. At that point, a clean install with Migration Assistant from user data only (not from a full disk clone) is the nuclear option that actually works long-term.