Short answer
Open Apple menu › System Settings › General › Storage to see what’s using the space. Then know what deleting does: a file only gives its space back once you empty the Trash, and a copy made in the Finder shares its data with the original. In our test, deleting that copy freed nothing.
Looking for copies that really take space? See where to look ↓
Start with your Mac’s Storage settings
- Choose Apple menu › System Settings, click General, then Storage.
- Look at the bar at the top: it shows what is using space, by category.
- Below it, macOS offers three recommendations: Store in iCloud, Optimize Storage, and Empty Trash automatically, which erases items that have been in the Trash for more than 30 days.
Find the biggest files. Click the Info button next to Documents to see large files and downloads, and sort them by size. The File Browser there shows how much space each folder takes.
Good to know. macOS also clears some things on its own when it needs room. Apple names caches and logs that are safe to delete, interrupted downloads and staged updates.
What “System Data” is
Apple describes System Data as the files the system itself uses: logs, caches, virtual memory files and other resources it needs while running. You can’t manage this category: macOS does, and its size goes up and down with what your Mac is doing. On older versions of macOS it was called Other.
Why “available” and “used” can overlap. The available space macOS shows includes purgeable caches, which it removes when it needs room. You can’t remove them by hand, so some space can be counted as both available and used at the same time.
“I deleted files and nothing changed”
Three common reasons.
1. The Trash isn’t empty
A file you move to the Trash keeps its space until you empty the Trash. In Finder › Settings › Advanced, “Remove items from the Trash after 30 days” does it for you. Items from iCloud Drive leave the Trash after 30 days either way. Emptying the Trash deletes the files for good, so look before you empty it.
2. The file was a copy made on the same disk
- Duplicating a file in the Finder doesn’t use extra space on your Mac’s disk. In our test, a 524 MB file and its Finder copy together used 524 MB, and deleting that copy freed nothing.
- Deleting the original while a Finder copy still exists freed nothing either.
- Apple explains the principle on Mac disks formatted APFS: a copy can share the same data as the original, and only the parts you later change take new space.
3. A local Time Machine snapshot still holds it
Snapshots can keep a deleted file’s data for a while. Apple says your Mac counts that space as available, deletes snapshots as they age or as space is needed, and that they don’t take the space you need to download, copy or install. Nothing to clean by hand.
Copies that really take space
A file you download again is a real second copy. In our test, the second download, saved as “(1)”, took its full 524 MB. Deleting it gave the space back once the Trash was emptied.
Where to look
- Your Downloads folder, and files you received more than once.
- Photos: click Duplicates under Utilities in the sidebar. Apple keeps the copies you remove in Recently Deleted for 30 days.
- Music: hold Option and choose File › Library › Show Exact Duplicate Items.
- Files in your folders: macOS has no duplicate finder. That’s what Find Duplicates in Ricly is for.
The right-click way
Find duplicate files with Ricly
- Install Ricly and open it. Turn on the Finder extension when it asks (one setting), then create your free account and verify your email. In Ricly › Modules, click Enable on Find Duplicates (it’s off at first).
- In Finder, right-click a folder, Downloads for example, and choose Ricly › Find Duplicates….
- Review the groups. When the copies carry different names, like “(1)”, nothing is checked for you. Then move the copies to the Trash.
- Empty the Trash to get the space back.
What it frees, honestly.
- The window shows how much the copies weigh. For copies of downloads, that is what you get back once the Trash is emptied.
- For copies made in the Finder, you get back less: they share their data with the original, as our test shows.
- Find Duplicates compares content byte for byte, so a renamed copy is found and a look-alike isn’t.
- It doesn’t look inside your Photos library. Use Duplicates in Photos for that.
For music, video and photo work
- Logic Pro. Apple lets you move the Sound Library to an external drive to save space on your Mac. You can also manage sound packs, with their total size shown at the top of the list.
- GarageBand. Clean Up removes the audio files a project no longer uses.
- Final Cut Pro. File › Delete Generated Library Files removes render and other generated files. Your original media stays, so they can be made again.
- Photos. In Photos › Settings › iCloud, Optimize Mac Storage keeps smaller versions on your Mac when space runs low, and the full-size originals in iCloud.
- Sample packs. A pack downloaded twice is two real copies, like any download. Find Duplicates on your samples folder groups them, even renamed.
iPhone and iPad backups
Old device backups can be large. In Storage they appear under iOS Files, with firmware files. To remove one:
- Connect the device, or select it in the Finder sidebar.
- In the General tab, click Manage Backups.
- Control-click the backup and choose Delete.
Mac storage full: common questions
Why is my Mac storage full when I barely have any files?
Look at Storage in System Settings first. System Data, iOS backups, the Trash and app libraries (Logic Pro sounds, Photos) can take more than your own documents.
Why didn’t deleting files free up space?
Three common reasons. The Trash isn’t empty yet. The file was a Finder copy sharing its data with another file: in our test, deleting it freed nothing. Or a local Time Machine snapshot still holds it, which macOS releases when it needs the space.
What is System Data, and can I delete it?
It’s the system’s own files: logs, caches, virtual memory and more. Apple says you can’t manage it: macOS does.
Does duplicating a file use more space?
Not when the Finder duplicates it on your Mac’s own disk: in our test, a copy of a 524 MB file added 8 KB. A file downloaded again takes its full size, and so does a copy on another drive.
Does deleting duplicates free space?
Copies of downloads, yes, once you empty the Trash. Copies made in the Finder free little or nothing, because they share their data.
Can a Mac find duplicate files on its own?
Photos and Music can find their own duplicates. For files in your folders, macOS has no duplicate finder.
Is it safe to remove duplicates with Ricly?
Nothing moves until you click and confirm. Everything goes to the Trash, so you can put it back from there. Keep one copy you trust, and empty the Trash once you’re sure.
