Mac Clean Up: clean up Mac storage safely, with everything going to the Trash

How to clean up Mac storage with Mac Clean Up

1. Click Mac Clean Up in the sidebar, or press ⇧⌘K (Go › Mac Clean Up). ⇧⌘D (Go › Duplicates) opens it straight at the duplicates.
2. If no scan has run yet, one starts straight away. Groups appear one by one as they’re found.
3. Click a group’s header or Review items to see its files. Most groups arrive with every item ticked; click a row to untick anything you want to keep.
4. Click Move N to Trash at the bottom of the group, then Move to Trash in the confirmation (“Move 3 items (1.79 GB) to the Trash?”).
5. Empty the Trash in Finder when you’re sure. Until then, the space isn’t freed, and everything can be put back.

The subtitle under the screen’s title says it plainly: “Nothing is deleted — items go to the Trash”. Mac Clean Up never empties the Trash for you.

What the scan looks at

While it works, Mac Clean Up shows a radar, three live counters (files checked, found so far, suggestions) and a checklist of steps, each ticked off with what it found:

• Downloads (three folders deep), Desktop and Movies and Pictures (two deep), and your Screenshots folder.
• Caches, logs, Xcode data & projects: your Library’s caches and logs, Xcode and package-manager caches, and build folders in old projects.
• Comparing files: identical copies, matched by content.
• Checking apps: apps you haven’t opened for three months.
• Comparing photos: look-alike photos, compared on your Mac.
• Every folder and cloud: only when Files is turned on. It reads Files’ index, so nothing is walked again or downloaded.

Click Scan Again in the toolbar to start over. The storage panel at the top is measured again at the same time.

Every group Mac Clean Up can find

Each file appears in one group only. Groups with nothing in them aren’t shown, and if nothing turns up at all you’ll see All tidy.

Copies across your clouds, Numbered copies & sync conflicts, Older versions, Very large files, Already saved elsewhere, Empty files, Names some clouds reject and Very long paths come from Files’ index of every folder and cloud, so they only appear with Files on. Apart from Empty files, they don’t count towards the “You can free up” total, because trashing a cloud copy frees space in that cloud rather than on your Mac, and they need a careful look first.

Shrink instead: keep the file, make it smaller

Some files are big but worth keeping. Big videos and Old screenshots have a Shrink instead button next to Move to Trash.

• For Big videos, it opens Compress Video with the ticked videos loaded and Balanced quality chosen. A 2.58 GB conference talk typically comes out at a fraction of the size.
• For Old screenshots, it opens Compress Images with the ticked screenshots loaded and HEIC chosen as the format.

Shrinking makes new, smaller copies; the originals stay where they are until you trash them. A sensible order is to shrink, check the results, then come back and move the originals to the Trash.

How to review duplicates and keep the right copy

Duplicate copies, Copies across your clouds and Similar photos are shown as sets rather than a plain list. Each set has the file’s name, how many copies there are and how much can be freed (“2 copies · 2.3 MB can be freed”), then a thumbnail for every copy with where it lives, its size and when it arrived.

• Each copy is labelled Keep (green) or Trash (red). Click any copy to keep it instead; the others in that set are marked for the Trash.
• The pill on the right sums it up, for example Keep 1, Trash 2. Keep All unmarks the whole set; Use Suggestion puts the suggested choice back.
• Right-click a copy for Quick Look or Show in Finder before you decide.
• At the bottom of the group, Use Suggestions applies the suggested keeper to every set at once, and Select None clears them all.

Which copy is kept

For identical copies, OneMacTools suggests keeping the copy outside Downloads first, then the oldest, then the one with the shortest path. That usually keeps the file you filed away and trashes the second download of it. For Similar photos, the largest file is kept, since it’s usually the original rather than a resized or re-saved copy.

How copies are matched

Duplicate copies are matched by content, not by name: files of the same size are compared by their first and last 64 KB, and only true matches are read in full and fingerprinted. Two files with different names but the same content are duplicates; two files with the same name but different content are not.

Similar photos uses Apple’s on-device image analysis to compare up to 1,500 of your newest photos. Screenshots are left out, because screenshots of the same app look alike without being copies. Photos checked once aren’t opened again on the next scan. For a standalone version that works on any folder you choose, see the Duplicate Finder tool.

The first 150 sets and the first 300 items in a group are shown; the rest are counted underneath.

Move to Trash and putting things back

When you confirm, the ticked files are moved to the Trash one by one. A green banner then says what happened, for example “Moved 3 items (1.79 GB) to the Trash.”, and how many couldn’t be moved, if any. The banner has three buttons:

• Put Back moves everything from that batch back to where it was and scans again.
• Share makes an image of how much you’ve freed (totals only, no file names).
• ✕ closes the banner.

Every batch is also recorded in History as Mac Clean Up with a line such as “Moved 3 items (1.79 GB) to the Trash — Old installers”, and a Put Back button that works later too. You can also drag items out of the Trash in Finder, or use Finder’s own Put Back. See History.

Put Back only moves an item if it’s still in the Trash and nothing else is now at its old location; anything it couldn’t restore stays listed so you can try again. Once you empty the Trash, the files are gone for good.

The storage panel and the System Data review

Above the groups, the Storage panel shows a bar across your disk and the space used by Applications, Documents, Developer, Photos, Music & TV, Mail & Messages, Trash, macOS and System Data, with “… used · … available” and when it was last measured. Trash opens the Trash in Finder; Explore Disk opens the disk map.

Click System Data or Developer to see what’s inside. Parts that match a Clean Up group (App caches, Logs, Build products (DerivedData)) have a Review button that jumps to that group. App data and Everything else open a review sheet that lists folders biggest first and only lets you tick those it can tell are safe: leftovers from apps you’ve deleted, caches that rebuild themselves, and iPhone or iPad backups over three months old. Virtual memory, Sleep image and local snapshots are marked Managed by macOS.

If you see “Turn on Full Disk Access to measure Mail, Messages, Photos and app data too.”, OneMacTools can’t yet read those folders’ sizes. Open Settings takes you to the right place; only file sizes are read. See Privacy permissions and Full Disk Access. What System Data actually is, in general, is explained in What is System Data on Mac?.

What Mac Clean Up never touches

• Your Trash. It never empties it; that’s always your call.
• Files only in iCloud. They take no space on your Mac, so trashing them would free nothing, and reading them would download them.
• OneMacTools’ own output folder. What you’ve just made is fresh work, not clutter.
• Caches of running apps, and OneMacTools’ own cache.
• Apple’s apps and OneMacTools itself, in Unused apps.
• Code projects. Scans of your folders skip developer folders (node_modules, build, .venv and similar) and any folder with a Git repository, so your source code never turns up as “forgotten downloads”. Build folders in old projects are offered separately, in Old project files.
• macOS’s own files. Virtual memory, the sleep image and snapshots are shown so you know what they are, never offered for the Trash.

Developers will find more detail on project folders in Dev & Agents, and AI app storage in AI Space.

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