Best Mac cleaner: the one built into macOS, plus three free tools for specific jobs

Why the best cleaner is the one already on your Mac

"Best Mac cleaner" lists almost always rank paid apps, because the sites writing them earn a commission when you buy one. This page starts from a different place: what is the job, and what is the smallest tool that does it well?

For most of the jobs a cleaner advertises, the answer is a part of macOS you may not have opened. Storage settings lists large files and old apps. Finder sorts any folder by size. Time Machine thins its own local snapshots. macOS marks cached iCloud files and downloaded media as purgeable and frees them when something needs the room. Memory is managed by the kernel, and the daily, weekly and monthly maintenance scripts run by themselves through launchd.

Apple Community regulars say this more bluntly than Apple does. In a thread asking whether a cleaner can make a Mac go faster, one wrote: "There is no Mac Cleaner that should ever be installed." Another: "There are no 3rd party apps that can directly improve performance." That is the view from people who answer thousands of "my Mac is slow" posts a year, and the pattern they see is that cleaners rarely cause the slowness, but they never fix it either.

The built-in tools have two real gaps. They do not uninstall an app's leftover files, and their view of where space goes is clumsy, especially for the System Data category. Howard Oakley's review of Storage settings calls that view "inferior to the likes of DaisyDisk and GrandPerspective". Those two gaps are where a narrow third-party tool earns its place.

Compare by the job, not the app

Here is every job a cleaner app offers, and the best tool for each. The ranking is by how well the job gets done, not by feature count.

Find what is using disk space. Built in: Storage settings, then Finder list view sorted by Size. Better: DaisyDisk, GrandPerspective or OmniDiskSweeper, which draw the whole disk as a map so a forgotten 40 GB folder jumps out in seconds.

Uninstall an app completely. Built in: drag to Trash, which leaves preferences and caches behind (usually a few MB, occasionally a few GB for developer tools). Better: AppCleaner, free, which lists the related files when you drop the app on it. The MacRumors default recommendation for years.

Empty caches. Built in: nothing, on purpose. Caches are current working files and macOS purges what it needs. Every third-party option here is theater that regrows in days; see should I clear cache on Mac for the two exceptions.

Remove old device backups, installers, downloads. Built in: Finder, Manage Backups for iPhone backups, Downloads sorted by size. No tool beats this.

Manage startup items. Built in: System Settings, General, Login Items and Extensions. The background items guide explains what each one is.

Scan for malware. Built in: XProtect, which runs silently and updates itself. A visible second opinion: Malwarebytes, which is also where "system optimizer" apps that fake problems end up classified.

Free up RAM or speed up the chip. Built in: the kernel, which already does this better than any button. Nothing to add. See memory cleaner apps.

Run maintenance scripts, rebuild Spotlight, flush DNS. Built in: scheduled automatically. Advanced users who want a manual trigger use OnyX, free.

Which tool for which problem

Follow the problem, not the product. Each step names the smallest tool that resolves it.

The last step is the one most "best Mac cleaner" searches are really about. A full disk makes a Mac slow only when it is nearly completely full. The rest of the time, slowness is one busy process, and the why is my Mac so slow guide is the better starting point.

The narrow free tools worth having

AppCleaner (free). A small window. Drag an app onto it and it lists the app plus its preference files, caches, support folders and launch agents, with checkboxes. Click Remove. It has worked the same way for over fifteen years and it is the first thing most forum regulars recommend when someone asks how to uninstall properly. It does not run in the background, scan anything, or ask for a subscription.

GrandPerspective and OmniDiskSweeper (free). Both scan a folder or the whole disk and show where the bytes are: GrandPerspective as a treemap of colored blocks sized by file size, OmniDiskSweeper as nested lists sorted largest first. One Hacker News user described the trade-off: "I've been using the free OmniDiskSweeper which gets the job done just fine, but isn't as pretty." Pretty is DaisyDisk's job.

DaisyDisk (paid, one-time). The polished disk map: a sunburst you can drill into, with a collection area for files you want to delete. Long-time users praise its staying power; one wrote in 2026, "They still update it, it works perfectly, no version 2.0 forced obsolescence." One caveat: the App Store version is sandboxed and cannot see inside some system locations, so for the System Data category it is less revealing than it looks. The direct download version has more reach.

OnyX (free, advanced). A Swiss army knife from Titanium Software that exposes maintenance scripts, cache deletion, Spotlight reindexing and dozens of hidden preferences. It is well established and free, and it is also the tool most likely to cause trouble in inexperienced hands, because it will do exactly what you tick. A Mac-Forums regular put it this way: "Just stick with something like OnyX, it has an established reputation and it's free." Another in the same thread: "if you check the wrong thing, your system can be rendered unusable." Use it if you know what each checkbox means. Skip it if you are reading this page to find out.

Pearcleaner and Mole (free, open source). Newer open-source options: Pearcleaner is an AppCleaner-style uninstaller with orphan-file search, and Mole is a command-line cleaner. Both are worth knowing about, both are maintained by individuals, so check the project page is active before relying on either.

The all-in-one cleaners: CleanMyMac, MacKeeper and friends

CleanMyMac, MacKeeper, MacCleaner Pro, BuhoCleaner and a dozen others bundle the jobs above into one window with a scan button and a big recovered-space number. The honest way to evaluate them is module by module.

Their uninstallers and large-file finders are good and roughly equal to the free tools. Their malware scanners are a reasonable second opinion. Their interface is the product: friendly, guided, reassuring, and a real benefit for someone who will never open Finder's list view. The is CleanMyMac worth it page goes through the most popular one in depth.

Their RAM, speed-up and cache modules are where the value thins out. They produce a number ("freed 4.2 GB") that macOS undoes within minutes or days, and nobody has shown a measurable speed gain from them. Apple Community's own user tip on Mac performance says such optimizers "at best have a placebo effect on optimizing your system."

The sharper criticism from forums is about marketing more than code. MacKeeper in particular spent years being promoted through aggressive pop-up ads and bundled installers, which is why older threads treat it harshly; the current product is a normal, if expensive, cleaner. CleanMyMac has never had that problem, but its scan totals are still built to impress. If you buy one, buy it for the uninstaller and the file finder, and ignore the speed tab.

The do-not-install category

Three kinds of app deserve a hard no, regardless of reviews.

Anything whose main promise is freeing RAM. macOS fills spare memory with file caches on purpose. A purge drops them, the number falls, and macOS reads them back from the SSD. Your Mac is briefly slower, not faster. Memory Clean, Memory Diag and the RAM buttons inside bigger cleaners all work this way. The memory cleaner apps page has the details and the one case where memory actually matters.

Anything that promises to speed up the processor. No app can make an M-series or Intel chip faster. The only thing that slows a chip is heat, and the fix is finding the process that makes it hot, which is an Activity Monitor job. The kernel_task page explains what throttling looks like.

Anything that found hundreds of problems before you asked. Malwarebytes classifies a whole category of "system optimizers" as potentially unwanted programs because, in its words, "These so-called 'system optimizers' use intentional false positives to convince users that their systems have problems." A scanner that reports 1,400 issues on a two-week-old Mac is selling fear. Close it, do not install it, and if it is already installed, remove it with AppCleaner.

A simple test: if an app's screenshots show a dial going from red to green, it is in this category.

How to clean a Mac without installing anything

1. Empty the Trash

   Control-click the Trash icon in the Dock and choose Empty Trash. Cleaner scans count Trash in their total; this is the same gain for free.

2. Act on Storage recommendations

   System Settings, General, Storage. Turn on Empty Trash Automatically, consider Optimize Storage (removes watched TV shows and old Mail attachments), and open Reduce Clutter to see your largest documents and unused apps.

3. Delete old iPhone and iPad backups

   Connect the device, select it in Finder's sidebar, click Manage Backups, remove backups for devices you no longer own. Several GB each.

4. Sort Downloads and Movies by size

   In Finder, open the folder, press ⌘2 for list view, click Size. Delete installers and old exports. Check Desktop too.

5. Uninstall apps you no longer use

   Storage settings, Applications, sort by Last Accessed. Drag unused ones to the Trash, or drop them on AppCleaner if you want the leftovers gone too.

6. Let System Data settle

   Give it a day. Local Time Machine snapshots and purgeable caches inside System Data shrink on their own when space is needed. If it is still large, the System Data guide lists the real causes.

7. Restart

   A restart clears swap, temporary files and any process that has been growing for days. It does more for a sluggish Mac than any cleaner.

When a third-party cleaner is the right call

There are honest cases. You install and remove a lot of software and want it gone properly: AppCleaner. You cannot work out where 80 GB went and Storage settings is no help: DaisyDisk or GrandPerspective. You maintain a Mac for someone who needs a guided, reassuring interface and will never open Finder in list view: a well-made all-in-one is a defensible purchase, used for its uninstaller and file finder.

What no cleaner does is answer the question people usually have when they go looking for one: why is this Mac slow, hot or loud right now? That is a question about processes, not files. Activity Monitor answers it if you know what the names mean. Safe to Quit answers it in plain words from the menu bar, watching each process over hours, naming the one that is making the Mac hot, loud or slow, and saying whether it is safe to quit. It is not a cleaner and it does not delete anything, which is rather the point.

So: built-in tools first, a narrow free tool for the one gap they leave, and a process monitor for the slow and hot questions. That combination covers everything a "best Mac cleaner" list promises, with less installed and nothing running in the background that you did not ask for.