Free up space on a developer Mac

Updated October 23, 2026

Developer tools are the biggest source of “System Data” on most developer Macs. Almost all of it is rebuildable, so it's safe to clear; the only cost is a slower next build.

Xcode

DerivedData (build products and indexes): ~/Library/Developer/Xcode/DerivedData. Safe to clear with Xcode closed.
Device support files for iOS versions you no longer test on: ~/Library/Developer/Xcode/iOS DeviceSupport.
Archives: ~/Library/Developer/Xcode/Archives. Keep the ones for builds you may need to symbolicate.

Simulators

xcrun simctl delete unavailable

This removes simulators for runtimes that are no longer installed. Simulator caches live in ~/Library/Developer/CoreSimulator/Caches, and runtimes you don't need can be removed in Xcode › Settings › Platforms.

Package managers

brew cleanup
npm cache clean --force
pnpm store prune
yarn cache clean

Swift Package Manager keeps its cache in ~/Library/Caches/org.swift.swiftpm, and each project's .build folder can be removed and rebuilt.

Docker

docker system prune

This removes stopped containers, unused networks and dangling images. Add -a to remove all unused images, and --volumes only if you don't need their data.

AI coding tools

Claude Code, Codex, Cursor and Gemini CLI keep caches, temporary files and old versions in your home folder. Their conversations and settings live next to them, so clear these by hand only if you know which files are which.

With Disklumo

Disklumo's Clean scan finds Xcode DerivedData, simulator caches, SwiftPM, npm, pnpm and Homebrew caches, and the caches and outdated installs of AI coding tools. Your projects and source code, AI conversations and local models are kept, anything in use is skipped, and Swift .build folders are left alone unless you add the project.

Questions

Is it safe to delete Xcode DerivedData?

Yes. DerivedData holds build products and indexes that Xcode recreates. Close Xcode first; the next build and indexing will take longer.

How do I remove old iOS simulators?

Run xcrun simctl delete unavailable to remove simulators for runtimes that are no longer installed, and remove unneeded runtimes in Xcode › Settings › Platforms.

Do it in one window

Disklumo scans your Mac, shows every item with its size and path, and moves what you choose to the Trash. Clean, uninstall apps, map your disk, watch live status and run maintenance. $17 once, for Apple Silicon Macs on macOS 14 or later.

See Disklumo