Most caches are safe because they rebuild themselves. The risk isn't the cache — it's deleting something that looks like a cache but isn't.
A cache holds data that can be recomputed from a source of truth. That is why deleting one is safe: the app regenerates it, slightly slower the next time. A database, a preference file, or an archive looks similar on disk and is not recomputable. If you can't explain what the source of truth is, don't delete it by hand — clear it from inside the app that owns it.
These regenerate on the next build or install. They are usually the largest reclaimable category on a developer's Mac.
| Cache | Location | Regenerates when |
|---|---|---|
| Xcode DerivedData | ~/Library/Developer/Xcode/DerivedData | Next build |
| iOS DeviceSupport | ~/Library/Developer/Xcode/iOS DeviceSupport | Device reconnected |
| Simulator caches / devices | ~/Library/Developer/CoreSimulator | Simulator next used |
| npm cache | ~/.npm (and ~/.cache tooling) | Next install |
| pnpm / yarn store | ~/.local/share/pnpm, yarn cache dir | Next install |
| Homebrew downloads | ~/Library/Caches/Homebrew | Next install/upgrade |
| pip cache | ~/Library/Caches/pip | Next install |
| Gradle / Maven | ~/.gradle, ~/.m2 | Next build |
| Cargo | ~/.cargo/registry | Next build |
| CocoaPods / SwiftPM | ~/Library/Caches/CocoaPods, SwiftPM caches | Next resolve |
| HuggingFace / ML model caches | ~/.cache/huggingface, and similar | Next download |
| Go build & module cache | ~/Library/Caches/go-build, ~/go/pkg/mod | Next build |
⚠️ Not caches, despite the folder name: Xcode Archives (~/Library/Developer/Xcode/Archives) are the release archives you upload to App Store Connect. Deleting them means re-archiving an old release. Treat them as project data, not build output.
~/Library/Caches/<bundle-id> — per-app caches. Rebuilt by the app./Library/Caches (system-wide app caches) — readable only with Full Disk Access, and best left to the apps.| Item | Why it needs care |
|---|---|
Docker's Docker.raw | Owned by the Docker runtime; shrink with docker system prune, never by deleting the file |
| Time Machine local snapshots | They are your local recovery points; tmutil can thin them, but the trade-off is real |
| iCloud / Dropbox / Drive local caches | Deleting the cache can trigger a full re-download |
| Mail data | Deleting the cache can force a re-index of your whole mailbox |
| Photos Library | A bundle, not a cache; manage inside Photos |
Logs (~/Library/Logs) | Usually safe, occasionally needed for support diagnostics |
/System — the sealed system volume. Modern macOS verifies it cryptographically./private/var/db — system databases.~/Library/Keychains — credentials.~/Library you can't identify. Use the owning app's own “clear cache” option instead.Blind “cleaners” guess from folder names, which is how people lose Xcode Archives or a mail index. A curated registry does the opposite: it names the specific paths that are known to be regenerable, says what each one is, and tags each entry Safe, Review or Caution so the decision stays yours. That's what Massive Disk's Space Savers view is — a registry rather than a guess, covering the caches above plus iOS backups, Mail downloads, user caches, logs and the Trash.
Whatever you clear, make it recoverable. Caches are meant to be disposable, but you only need one wrong deletion to learn why staged, Trash-based cleanup matters. Massive Disk never hard-deletes: every removal from the cleanup queue, Space Savers, Duplicates or the uninstaller lands in the Finder's Trash first.
Mostly, but not wholesale. Individual app caches under ~/Library/Caches are safe because they rebuild. Blanket-deleting the entire folder can force large re-downloads (cloud sync clients, mail index) and occasionally removes state an app doesn't rebuild cleanly.
Yes — Xcode recreates it on the next build. Do not confuse it with Xcode Archives, which are your release archives and should be kept.
No; caches refill as you use your Mac. It resets the clock and recovers space now, which is why the ongoing habit is to re-scan periodically rather than clean once.
Massive Disk is a native Apple Silicon app that maps every byte of your storage across six visualizations — then gives you safe, reversible ways to get space back. Scanning is free forever; cleanup tools are Pro.