How to clear the cache on a Mac: which caches, when it helps, and how to do it safely

"Clear your cache" is the most common advice on the internet for a Mac that is misbehaving, and it is right about a third of the time. This post covers where the caches are, how to clear each one by hand, and the three cases where it is worth doing.

What a cache is, and why clearing it is not a speed-up

A cache is a copy an app keeps so it does not have to do the same work twice: thumbnails it has already drawn, web pages it has already downloaded, code it has already compiled. When the cache is there, the app is quick. When you clear it, the app rebuilds it the next time it needs it, and it runs slower while it does.

So clearing caches to make a healthy Mac faster usually does the opposite for a day or so. macOS also trims caches by itself when the disk runs short. We say more about this in does a Mac need a cleaner?

There are three situations where it is the right move:

1. One app misbehaves. It shows stale content, crashes on launch or will not load something it used to. A corrupt cache is a common cause, and clearing just that app's cache is a cheap first step.
2. You need the space now. Caches can run to several gigabytes, and on a nearly full disk that matters.
3. Privacy. Browser caches and history are a record of where you have been.

The caches on your Mac, and which ones to touch

Location	What is in it	Clear it?
~/Library/Caches	Caches for the apps you run, one folder each	Yes, app by app
~/Library/Containers/<app>/Data/Library/Caches	Caches for sandboxed apps, including most App Store apps	Yes, app by app
Browser profiles	Web cache, history and cookies, per browser and per profile	From the browser itself
/Library/Caches	Caches shared by all users and system services	Leave it
/System/Library/Caches	macOS's own	You cannot. macOS protects it

The ~ means your home folder. Your Library folder is hidden: in Finder, choose Go › Go to Folder (⇧⌘G) and type ~/Library/Caches.

Clearing one app's cache by hand

1. Quit the app. Clearing a cache while the app is using it is how you get the corruption you were trying to fix.
2. Open ~/Library/Caches and find the app's folder. It is usually named after the app's bundle identifier, such as com.spotify.client or com.microsoft.VSCode.
3. Open that folder and move its contents to the Trash. Leave the folder itself where it is.
4. Open the app again and check that the problem has gone.
5. Empty the Trash a few days later, once you are sure nothing needed it.

If you cannot find the app in ~/Library/Caches, it is probably sandboxed. Look in ~/Library/Containers, find the app's folder, and go into Data/Library/Caches inside it.

Avoid the one-line Terminal versions you will find elsewhere, such as rm -rf ~/Library/Caches/*. They clear every app's cache at once, including the caches of apps that are running. They skip the Trash, so there is no undo. And they save you about thirty seconds.

Clearing browser caches

Clear browser caches from inside the browser. The browser knows which of its files are safe to remove while it runs.

• Safari: turn on Settings › Advanced › Show features for web developers, then choose Develop › Empty Caches (⌥⌘E). This clears the cache and keeps your history and logins. History › Clear History removes history along with cookies and website data.
• Chrome, Brave, Edge, Arc: press ⇧⌘⌫, pick a time range, and tick only Cached images and files if you want to stay signed in to everything.
• Firefox: Settings › Privacy & Security › Cookies and Site Data › Clear Data, with only Cached Web Content ticked.

Each browser profile has its own cache, so if you use a work profile and a personal profile, clear each one.

The DNS cache

If one website will not load on your Mac but loads fine on your phone, your Mac may be holding an out-of-date address for it. Flush the DNS cache in Terminal:

sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder

Nothing is deleted, and macOS rebuilds the cache as you browse.

What to leave alone

• /Library/Caches and anything under /System. These are macOS's own. Clearing them by hand gains little, and the System folder is protected anyway.
• Logins and cookies, unless you mean to sign out of everything. Most "clear browsing data" screens tick cookies by default.
• Developer caches you are using today. Xcode DerivedData and package-manager caches are safe to remove, but your next build will be slow while they rebuild. There is a separate post on those.
• Anything you cannot identify. Look up a folder name before you remove it.

Doing it with SweepyMac

Clearing caches by hand is fine for one app. For the whole Mac it is a lot of folders, so this is the job we built SweepyMac's first two screens for, and we built them to work the way the manual method above does.

Smart Scan looks at your user caches, application logs and saved app state in one pass, totals what can be reclaimed, and touches nothing until you press Clean. Cleanup lists the same groups along with developer caches and leftovers from apps you have uninstalled. Only the conservative groups start ticked, and each group opens up to show the exact files inside. Smart Scan or Cleanup? explains the difference.

Removed files go to the Trash, and every clean has an Undo, which is step 3 of the manual method done for you. The Privacy tab in Protection does the browser side: cache, history and cookies for Chrome, Brave, Edge, Arc, Vivaldi, Chromium, Firefox and Safari, one row per profile, with nothing pre-selected. For Safari it can clear only the cache, because macOS protects the rest. The DNS flush is a button on the Performance screen.

Some things SweepyMac never offers to remove: anything in /Library or /System, Xcode Archives, iOS DeviceSupport, and Docker images. Cleanup only works inside your own user folders, so it never needs your administrator password.

It will not make a healthy Mac faster, and the same is true of any other app that clears caches. What it does is clear the right caches in a couple of minutes and let you put back anything you did not mean to remove. SweepyMac is free for three days, then from $14.99 a year or $59.96 once. Download it from its page.