A macOS update told me I needed 25 GB more. Finder said "System Data: 180 GB" and nothing else. If you write code on a Mac, most of that is probably yours: build output, package caches, simulators, containers and models. The good news is that a lot of it recreates itself.

Here's what I found, where it lives, and the right way to clean each one.

Start here: what recreates itself

These are copies. Delete them and the tool that made them makes them again when needed. Close the tool first.

What Where Clean it with

Xcode build data ~/Library/Developer/Xcode/DerivedData Quit Xcode, empty the folder

Xcode iOS symbols ~/Library/Developer/Xcode/iOS DeviceSupport Empty the folder

npm cache ~/.npm/_cacache npm cache clean --force

pnpm store ~/Library/pnpm/store pnpm store prune

Yarn cache ~/Library/Caches/Yarn yarn cache clean

pip cache ~/Library/Caches/pip pip cache purge

uv cache ~/.cache/uv uv cache clean

Homebrew cache ~/Library/Caches/Homebrew brew cleanup -s

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