Xcode DerivedData No Space Left

Xcode `No space left on device` errors often point at DerivedData or ModuleCache, but the safest fix is to separate rebuildable cache from archives, simulator runtimes, and project state.

Usually safer to clean

• DerivedData after Xcode and xcodebuild jobs are stopped
• ModuleCache.noindex when the build can regenerate modules
• Old build logs and temporary intermediates after preserving failure logs you need

Review before deleting

• Archives used for releases, crash symbolication, or App Store history
• Simulator runtimes required by active projects or CI matrix jobs
• DeviceSupport folders for devices still used by QA or release testing

Read-only checks first

du -sh ~/Library/Developer/Xcode/DerivedData
du -sh ~/Library/Developer/Xcode/Archives
du -sh ~/Library/Developer/CoreSimulator
du -sh ~/Library/Developer/Xcode/iOS\ DeviceSupport 2>/dev/null