Where does your Mac store cache, and is it safe to delete?

“Clear your cache” is the standard tech-support answer to slow Macs, but it’s vague advice. Cache lives in three different places on macOS, and the answer for “safe to delete?” depends on which one.

The three cache locations

1. ~/Library/Caches/ — per-user caches for the apps you run. Browser caches, app thumbnails, Spotify's media cache, etc.
2. /Library/Caches/ — system-wide caches accessible to all users. Usually small.
3. /System/Library/Caches/ — macOS system caches. Don't touch.

What’s safe to clear

Generally safe:

• Contents of folders inside ~/Library/Caches/ for apps you use casually
• Browser caches (clear from the browser itself, not Finder)
• App-specific caches you can identify

Not safe:

• Anything in /System/Library/Caches/
• The cache folder itself (delete the contents, not the folder)
• Caches for apps that are currently open

How to see your biggest caches

du -sh ~/Library/Caches/* 2>/dev/null | sort -h | tail -15

That prints your 15 largest cache folders, sorted. Anything above a few hundred MB is worth a closer look.

How to clear caches safely

1. Quit the relevant app first.
2. Open Finder, hit Cmd + Shift + G, and enter ~/Library/Caches.
3. Open the folder for the app whose cache you want to clear.
4. Select all the contents (not the folder itself), drag to Trash.
5. Empty the Trash.

What clearing cache actually does

Realistically, two things:

• The next launch of that app is slightly slower (it rebuilds the cache)
• You free some disk space — sometimes meaningful, sometimes not

It almost never fixes “slow Mac” problems beyond very specific scenarios (corrupted thumbnail caches, etc.). If you’re hoping for a magic speed boost, you’ll be disappointed.

What it doesn’t help with

Clearing cache doesn’t:

• Remove duplicate files
• Delete old downloads
• Clean up uninstalled app data
• Make Spotlight search faster

On duplicates in caches

One niche thing caches do is duplicate your media: Spotify’s offline cache stores songs you also have in iTunes; Photos rebuilds thumbnails that already exist in Photos.app; Mail caches every attachment. Most of this is fine and clears itself.

What’s worth checking is whether your actual documents and media have duplicates. Download Dupe for that. It uses SHA-256 hashing to find byte-identical files, moves dupes to the Trash (never permanent delete), and skips system files and app bundles. $14.99 once.