Finding specific things

Where your disk space actually went

Updated 2026-07-31 · 5 min read

Storage settings tells you there is a problem. It rarely tells you where. Work through these in order — the first three usually finish the job.

Measure before deleting

du -h -d 2 ~ 2>/dev/null | sort -hr | head -25

That single command usually identifies the culprit in seconds. Run it on / with sudo if your home folder is not the problem.

1. Developer caches, if you write code

• ~/Library/Developer/Xcode/DerivedData — build artefacts, regenerated on demand
• ~/Library/Developer/Xcode/iOS DeviceSupport — symbols for every iOS version you ever

connected, often 30 GB+

• ~/Library/Developer/CoreSimulator/Devices — old simulators
• node_modules folders in abandoned projects

All safely deletable. All invisible to Spotlight.

2. Mail

~/Library/Mail grows without limit. In Mail → Settings → Accounts → Account Information, set Download Attachments to Recent or None for accounts you keep for archive.

3. Old installers

find ~/Downloads -name "*.dmg" -o -name "*.pkg" | xargs -I{} du -sh {} | sort -hr

.dmg and .pkg files are the classic forgotten gigabytes.

4. Photos and iCloud

If Optimise Mac Storage is off, every original is on disk. Turning it on in Photos → Settings → iCloud moves originals to iCloud and keeps smaller local versions.

5. Local Time Machine snapshots

macOS keeps hourly snapshots on the boot disk. It reclaims them automatically under pressure, but you can see them:

tmutil listlocalsnapshots /

What not to bother with

• Cleaning "System Data" — much of it is snapshots and caches macOS manages itself
• Third-party cleaners — most of the space they find is caches that regenerate immediately
• Deleting language files — saves little, breaks localisation

Then check the drives you forgot

Space problems are often solved by remembering what is already archived elsewhere. Being able to search a drive that is unplugged makes "do I still need this locally?" answerable without plugging anything in.

Common questions

Is it safe to delete iOS DeviceSupport?

Yes. Xcode re-downloads symbols when you next connect a device running that version.

Do Mac cleaner apps actually help?

They mostly delete caches that regenerate within days. The lasting wins are developer caches, mail attachments and media.