Mac caches explained, and which ones are safe to clear

Three separate cache locations exist on macOS and they carry different risks. The user level ones are broadly safe to empty and give back less space than people expect. The operating system ones should be left alone. The real danger sits elsewhere, in two folders that look like clutter and hold working data.

Clear your caches is the standard suggestion and it is not actionable without knowing which ones. Here is the list.

The three Mac cache locations

The tilde matters more than anything else on that list. A path starting with one is inside your own home folder and belongs to you. The same path without it is system wide and shared by every account, which is a different proposition entirely.

The last row is less of a warning than it looks. Since Big Sur the system volume has been sealed as a Signed System Volume and mounted read only, which holds through Monterey, Ventura, Sonoma, Sequoia and Tahoe. On any of them you cannot delete from it, even as an administrator. Advice telling you to avoid that folder is describing a door that is already locked.

Browser caches are not in these folders

Most people asking about Mac caches mean their browser. Browsers do not keep theirs where the rest of this page is looking.

Safari clears its own from the History menu or from Settings under Privacy. Chrome has Clear Browsing Data in its settings. Firefox keeps the equivalent under Privacy and Security. Each is a switch inside the application rather than a folder to find. Each gives you control over what goes, which Library never does.

Use the browser's own control rather than deleting its Library folder. Removing the folder by hand takes the site data with it, which is what signs you out of everything. The in application version separates cached files from cookies and logins, so you can clear one and keep the other.

The two Library folders that are not caches

This is where people lose things. Both sit in the same Library folder. Both look like accumulated cruft. Neither holds anything that rebuilds itself.

Read more: The hidden Library folder on a Mac and what lives in it.

Group Containers is the expensive mistake. It sits alphabetically near Containers, it is one of the largest folders in Library and it contains no cached data at all. On a Mac running Outlook it holds every message that client has downloaded. People clearing Library broadly have deleted years of mail this way and only discovered it on the next launch.

Application Support is the quieter version of the same problem. It looks like leftovers from applications you no longer run. Some of it is. The rest is licences, settings and in some cases the only copy of work an application chose to store there rather than in Documents.

Why clearing Mac caches frees less space than promised

Caches exist because rebuilding something is slower than keeping it. Remove them and the applications rebuild them, sometimes within minutes of the next launch.

Read more: What System Data on a Mac is.

What macOS will not do is prune them for you on any schedule. It rebuilds caches readily and removes them rarely, which is why a folder nobody has touched in five years is as large as it is.

An Apple Support community reply puts it plainly: clearing the user Caches folder tends not to save much, because macOS and your applications repopulate it as soon as they run again. The space returns to you and then leaves again.

Which is the thing to weigh before spending an evening here. The genuinely large folders on a Mac are rarely caches. A browser cache measured in hundreds of megabytes is not the reason a 500GB disk is full. The storage bar breakdown points at the folders that are. On most Macs Apple Mail is one of them.

The one cache worth deleting on purpose

Almost everything described so far rebuilds itself. One category does not.

Caches belonging to applications you have removed are orphans. Nothing regenerates them, because nothing is left to do the regenerating. After a few years of installing and uninstalling, Caches holds folders named for software that departed long ago. Those are the only entries where deleting gives the space back and keeps it.

They are also the easiest to identify. The folder names are bundle identifiers, written as reverse domain names, so a folder called com.adobe.something on a Mac with no Adobe software is safe by inspection rather than by guesswork.

How to clear Mac caches safely

Do this in Finder, not in Terminal. You will find rm recommended for it. That command removes files with no Trash to retrieve them from and no confirmation. It does not forgive a mistyped space in a path. Every step below can be undone.

1. Quit every application first. A running app will hold files open and rewrite what you remove.
2. Open your own Library. Use Go to Folder in Finder and give it ~/Library/Caches.
3. Look before selecting. Switch to list view, put the largest first and read what they are called. Get Info on anything ambiguous. Anything you still cannot identify stays.
4. Take the contents, not the folders. Open each cache folder and remove what is inside it, leaving the folder itself in place.
5. Move to Trash rather than deleting outright. Nothing is gone until you empty it, which gives you a day to notice a problem. A recent back up makes the whole exercise less tense.
6. Restart, then use the Mac normally for a day. Only empty the Trash once nothing has complained.

The move it first test. If a folder is large and you cannot work out what it is, drag it to the desktop rather than the Trash. Use the Mac for a few days. If nothing breaks it was safe to remove. You have proved that rather than guessed it.

What actually breaks when you clear a cache

Very little, when you stay inside the user caches. The realistic outcomes are worth knowing so you can tell a symptom from a fault.

• Applications launch slowly once. They are rebuilding what you removed. The second launch is normal.
• You are signed out of some websites. Browser caches and site data live near each other.
• Thumbnails and font caches regenerate. Previews and font databases rebuild as they are needed, which can take a while on a large library or a machine with many fonts installed.
• An application forgets recent items or window positions. Annoying rather than damaging.

What does not happen, if you stayed in the right folders, is data loss. That is the whole reason the distinction between a cache and a store matters.

One thing people arrive looking for and will not find here is the DNS cache. That is a separate thing living in memory rather than on disk. It is flushed with its own command and has no bearing on storage.

When clearing a cache is the right answer

There is a good reason to do this and it has nothing to do with space.

An application behaving oddly, showing stale content or failing at something it used to manage is a candidate for a corrupt cache. Clearing that one application's cache folder is a reasonable early step. It is cheap because the cache rebuilds anyway.

Booting into Safe Mode is the gentler version of the same idea. It clears system level caches on the way up and leaves your user caches untouched, which is why it fixes some problems and does nothing at all for others.

That is a targeted fix for a specific fault. Emptying every cache on the Mac to reclaim space is a different activity with a much worse ratio of effort to result. When space refuses to return after a delete, snapshots are the usual reason rather than caches.