Finding specific things

When the disk is full right now

Updated 2026-07-31 · 4 min read

Startup disk full, cannot save, cannot work. The quickest gigabytes, in order.

First, buy headroom

Empty the Trash — including per-app and per-drive trashes:

rm -rf ~/.Trash/*                 # or Finder → Empty Trash

macOS may already be blocked from reclaiming purgeable space; a manual snapshot thin frees the fastest gigabytes:

tmutil listlocalsnapshots /
tmutil thinlocalsnapshots / 10000000000 4     # ask for ~10GB

Local Time Machine snapshots are usually the single biggest instant win.

The five-minute audit

du -h -d 1 ~ 2>/dev/null | sort -hr | head

Go one level deeper into whatever dominates. Almost always one of:

• ~/Library/Developer — Xcode DerivedData and device support (delete freely)
• ~/Library/Caches — safe to clear
• ~/Downloads — old installers and disk images
• ~/Movies, iMovie/Final Cut render files
• A runaway log or a stuck-mounted .dmg

Fast, safe deletes

rm -rf ~/Library/Developer/Xcode/DerivedData/*
rm -rf ~/Library/Caches/*                       # apps rebuild these
find ~/Downloads \( -name "*.dmg" -o -name "*.pkg" \) -delete

Unmount stuck disk images

An old .dmg mounted holds space:

hdiutil info | grep image-path

Eject any you do not need.

What not to do in a panic

Do not delete inside ~/Library/Containers, /System, or anything you cannot identify. Do not empty Photos' Recently Deleted expecting instant space — it frees after its own timer. Purgeable space and snapshots are the emergency lever; caches and Downloads are the follow-up; everything else waits until you are not panicking.

Common questions

How do I free space immediately on a full Mac?

Empty Trash, thin local snapshots (tmutil thinlocalsnapshots), clear Xcode DerivedData and Caches, delete old installers. Snapshots are usually the biggest instant win.

Is it safe to delete everything in ~/Library/Caches?

Yes — apps regenerate caches. Some apps will be slower on first launch afterwards.