How to Clear Cache on Mac (Safely, and Only What's Safe)

Clearing cache on a Mac is safe, because a cache is by definition data an app can rebuild. The risk is never in deleting a real cache; it is in blind tools and blind commands that treat everything in a Library folder as disposable and take an active profile or a preferences file along with the junk. The skill worth learning is telling cache apart from data, and then clearing only the cache.

Here is what each kind is, where it lives, and how to clear it without collateral damage.

Cache, state, and data are three different things

Everything an app keeps outside its bundle falls into one of three buckets, and only the first is safe to delete freely:

  • Cache is recomputable: rendered thumbnails, compiled output, downloaded files kept for speed. Deleting it costs only a slower next launch.
  • State is your session: open windows, scroll positions, drafts. Losing it is annoying but not catastrophic.
  • Data is irreplaceable: your messages, your photos library, your saved logins. Deleting it is a real loss.
A cache lookup branching into a fast cache hit or a miss that fetches source data and rebuilds the cache
A cache hit returns immediately. A miss fetches source data, rebuilds the disposable copy, and stores it for the next request.

The folders below mix these, which is exactly why "clear all cache" tools are risky. A folder inside ~/Library/Caches is usually cache, but not always, and the folders next to it often are not.

Where cache lives on a Mac

  • ~/Library/Caches/ holds per-app user caches, the largest everyday group. Each subfolder is named by bundle identifier, like com.google.Chrome.
  • /Library/Caches/ holds system-wide caches.
  • /System/... is protected by System Integrity Protection and is not yours to touch. Never try.

Preferences deserve a special warning. Files in ~/Library/Preferences are your settings, not cache, and macOS caches them in memory through a daemon called cfprefsd. If you delete a .plist by hand while the app or cfprefsd still holds it, the daemon simply writes it back on quit, so the deletion looks like it did nothing. Preferences should be changed with defaults, not deleted as if they were cache.

The caches worth clearing, and the big ones

Find your largest caches before clearing anything:

du -sh ~/Library/Caches/* 2>/dev/null | sort -h

The heaviest lines are usually:

  • Browsers. Safari, Chrome, and others hold gigabytes of cached pages and media. Clear these from the browser's own settings, which is safer than deleting the folder, since it separates cache from your history and logins.
  • Developer tools, which dwarf everything else on a coding Mac. Xcode's ~/Library/Developer/Xcode/DerivedData can reach tens of gigabytes, and package managers keep their own stores: brew cleanup clears old Homebrew downloads, npm cache clean --force clears the npm cache, and ~/Library/Caches/ holds caches for Swift Package Manager, pip, and others.
  • QuickLook thumbnails, rebuilt on demand: qlmanage -r cache.

Always quit the owning app first. Cache files are often open or memory-mapped while the app runs, and deleting them mid-write can corrupt the cache database the app depends on, which turns a space cleanup into a broken app.

The safer way, by category with review

Doing this by hand works but is tedious and easy to get wrong, since folder names do not always match app names and some folders under Caches are not cache at all. A cleaner that groups caches and shows each one's size and location before touching anything removes the guesswork. Mole's Clean view scans across categories (app and system caches, browsers, developer and AI tool caches, design apps, logs, purgeable snapshots, and leftovers from uninstalled apps), lists what it found with sizes, sends removals to the Trash so they stay recoverable, and truncates live log files in place rather than pulling them out from under a running app. It deliberately skips what should never be swept: browser profiles and history, iCloud documents, local AI model stores and chat transcripts. That skip-list is the real value over a blind rm -rf of a Caches folder.

What not to clear, even in the name of cache

  • AI assistant chat history and transcripts. These sit near caches but are irreplaceable data. Never delete them for space.
  • Preferences and saved logins, as opposed to disposable cache.
  • Anything under /System.
  • Any folder whose purpose you cannot identify.

The rule is the one that keeps every Mac cleanup safe: if you cannot tell what a file is for, do not delete it.

The short version

A cache is anything an app can rebuild, which is why clearing it is safe and why the space slowly returns; treat it as maintenance, not a one-time fix. Learn to separate cache from state and data, find your big caches with du -sh ~/Library/Caches/* | sort -h, clear browsers from their own settings and developer caches with brew cleanup and by emptying DerivedData, quit apps first, and never delete preferences, chat histories, or anything you cannot identify. Caches are also the largest part of the System Data block, so clearing them well is often the biggest safe win when that number grows.