A no-bullshit guide to cleaning up your Mac's disk

Most “clean up your Mac” guides are written for SEO, not for you. They tell you to “remove temporary files” without saying which ones, recommend whatever cleaner app pays the highest affiliate, and pad out the list to 50 items. Here’s the short version that actually moves the needle.

What actually works

In rough order of payoff:

1. Downloads folder. Sort by size. Delete anything that's an installer, an old export, or something you've already used.
2. Old iOS backups. Plug your phone in, open Finder, click "Manage Backups." If there's an entry for a phone you don't own, delete it.
3. Mail attachments cache. Mail > Settings > Accounts > Advanced. Set "Download Attachments" to "None." Old cached attachments live in ~/Library/Containers/com.apple.mail/Data/Library/Mail Downloads/.
4. Photos library. Photos > Settings > iCloud > Optimize Mac Storage.
5. Large media files. Run find ~ -type f -size +1G 2>/dev/null in Terminal.
6. Duplicates. Surprisingly large on most Macs and invisible to Finder.

What’s a waste of time

To save you reading another listicle:

• “Clear all caches” — they regenerate immediately and just make your next app launch slower
• “Remove old language files” — saves maybe 200 MB on the entire system, not worth the risk
• “Defrag your disk” — macOS doesn’t need this and hasn’t for over a decade
• “Reset PRAM” — does nothing for disk space
• “Disable Spotlight indexing” — saves nothing meaningful, breaks search
• Paying for a $90/year cleaner app to do the above

The Terminal shortcut

If you want the one command that tells you where to look:

du -sh ~/* 2>/dev/null | sort -h | tail -10

Whatever folder is at the bottom of that list is where to focus. Run it again on subfolders to drill down:

du -sh ~/Documents/* 2>/dev/null | sort -h

On cleaner apps

The big “clean your Mac” apps mostly do three things: delete files macOS would have managed itself, scare you with red warnings about “junk” that doesn’t exist, and bill you on a subscription. The only category they actually do well is duplicate detection — and even that, only some of them do correctly.

If you want a duplicate finder specifically, Download Dupe. It’s $14.99 once, hashes files with SHA-256 so it only flags byte-identical matches, moves dupes to the Trash (so they’re recoverable for 30 days), and never touches system files. It does one thing and does it right.

Everything else on this list you can do with Finder, Terminal, and 20 minutes.