Mac hard drive cleanup — the modern checklist

Most “Mac hard drive cleanup” guides still tell you to defrag, repair permissions, and reset PRAM. None of those help on a modern Mac. Here’s the actually-relevant checklist for macOS Sonoma, Sequoia, and later on Apple Silicon and Intel SSDs.

What’s changed

Three things that used to be advice but aren’t anymore:

• Defragging. SSDs don’t fragment in the way HDDs did. macOS hasn’t needed manual defrag in over a decade.
• Repairing permissions. System Integrity Protection makes most permission changes impossible, and “Repair Disk Permissions” doesn’t exist anymore.
• Resetting PRAM/SMC. Doesn’t free disk space. Apple Silicon Macs don’t even have these to reset.

The modern checklist

In rough order of payoff:

1. Empty Downloads of installers and ZIPs. Sort by Kind, batch-delete the DMGs and ZIPs.
2. Delete old iOS backups. Finder > iPhone > Manage Backups. Wipe anything from a phone you don't own anymore.
3. Optimize Photos for iCloud. Photos > Settings > iCloud > Optimize Mac Storage. Reclaims the local copy of your iCloud library.
4. Clear Mail attachments. Mail > Settings > Accounts > Advanced > "Download Attachments: None."
5. Audit Applications. Apps you haven't opened in a year? Go.
6. Hunt large files. find ~ -type f -size +1G 2>/dev/null
7. Clear Xcode caches (if applicable). ~/Library/Developer/Xcode/DerivedData often holds 20+ GB.
8. Hunt duplicates. Last big bucket.
9. Empty Trash. Or better, set it to auto-empty after 30 days.

Terminal one-liners for each

du -sh ~/* 2>/dev/null | sort -h          # biggest home folders
du -sh ~/Library/* 2>/dev/null | sort -h  # biggest library folders
find ~ -type f -size +1G 2>/dev/null      # files over 1 GB
ls -lah ~/Library/Application\ Support/MobileSync/Backup/  # iOS backups
rm -rf ~/Library/Developer/Xcode/DerivedData/*  # Xcode caches (re-builds on next compile)

What’s actually new on modern Macs

A few features that didn’t exist in older guides:

• Storage Settings recommendations. System Settings > General > Storage gives you “Store in iCloud,” “Optimize Storage,” “Empty Trash Automatically,” and “Reduce Clutter.” Decent first pass.
• iCloud Drive optimisation. Files not used recently get evicted from local disk (small download cloud icon shown) and re-downloaded on demand.
• APFS snapshots. macOS keeps automatic Time Machine local snapshots. tmutil listlocalsnapshots / to see; auto-purge when space is tight.

Don’t waste time on

A list of things that won’t help:

• “Cleaning RAM” — disk space and RAM are unrelated
• Disabling Spotlight — saves negligible space, makes search worse
• “Removing language packs” — saves maybe 200 MB and risks breaking apps
• Subscription cleaner apps that auto-renew at $90/year

On the duplicates step

The reason it’s at the bottom of the list is also the reason it’s worth doing: every other step has a Finder-level UI. Duplicates don’t. They’re invisible without hashing.

Download Dupe, which does SHA-256-based duplicate detection across whatever folders you pick. Trash-only, never permanent deletes, never touches system files, $14.99 one-time. Pairs well with this whole list — runs after you’ve cleared the obvious junk.