How I reclaimed 47GB on my MacBook by cleaning developer project junk

The article describes how a developer reclaimed 47GB of storage on their 512GB MacBook by manually deleting accumulated project junk, including 18GB from `node_modules` folders, 14GB from Unity Library folders, 9GB from Xcode DerivedData, and 6GB from Python virtualenvs. The author notes these files are safe to delete as they regenerate automatically, and provides terminal commands for manual cleanup. After the manual process, the author created a paid tool called PolySweeper ($14.99) that automates scanning and deleting these developer-specific files while running fully offline.

Last week I ran out of disk space mid-deploy. That annoying "Your startup disk is almost full" notification. I had a 512GB MacBook and somehow had less than 8GB free. So I started digging. What I found surprised me. The culprits Here's the breakdown of what was eating my storage: node modules — 18GB Every JavaScript project has one. They're never small. A typical React project pulls in 300–500MB of dependencies. I had projects from 2021 I'd completely forgotten about — each one with an intact node modules folder taking up space. The good news: they're completely safe to delete. npm install or yarn , or pnpm regenerates them instantly. Unity Library folders — 14GB If you've ever used Unity — even just for a game jam or a tutorial — your project has a Library folder. Unity uses it as a local cache for imported assets. It regenerates automatically when you open the project. I found four old game jam projects I'd abandoned. Combined Library size: 14GB. Xcode DerivedData — 9GB Xcode stores build artifacts, indexes, and intermediate files in ~/Library/Developer/Xcode/DerivedData. It grows silently over time. Mine had build caches from apps I no longer maintain. Safe to delete via Xcode → Preferences → Locations → DerivedData → arrow button. Or just nuke the folder directly. Python virtualenvs — 6GB Every python -m venv or conda create leaves behind an isolated environment with its own Python installation and packages. I had virtualenvs from tutorial projects dating back to 2020. The fix I went through each category manually this time. It took about 40 minutes and recovered 47GB. After doing this, I built a tool to make it automatic: PolySweeper https://pixentinteractive.gumroad.com/l/nuppjv . It scans your Mac, finds all of these by category, shows the size, and lets you delete with a confirmation step. Runs fully offline — nothing leaves your machine. If you want to do it manually, here's the quick version: Find largest node modules folders find ~ -name "node modules" -type d -prune | xargs du -sh | sort -hr | head -20 Find Unity Library folders find ~ -name "Library" -type d -path " /Assets/../Library" | xargs du -sh 2 /dev/null Clear Xcode DerivedData rm -rf ~/Library/Developer/Xcode/DerivedData Worth running even if you think your disk is fine. Most developers I know have 10–40GB hiding in these folders. If you want the automated version: PolySweeper — macOS disk cleaner built specifically for developers. One-time $14.99.