What your files add up to is not what your disk holds.
The Finder counts every copy. On APFS a copy can be a clone that takes no space of its own. Clonemap shows how much of your Mac is stored once, where it lives, and what a snapshot is holding back.
Free · Universal, for Apple silicon and Intel · macOS 11 or later
v1.4.4 · What's new
What the files add up to
654.9 GiB
What the disk holds
689.7 GiB
Stored once
23.1 GiB
A 926 GiB drive, 4,102,945 files, not one of them opened.
Your Mac's sizes don't add up. Here is why.
The Finder counts every copy
Duplicate a file, copy it within the same drive, or let Photos, Logic or a virtual machine keep its own copies. On APFS such a copy is often a clone that shares its blocks with the original. Get Info and folder sizes still count it in full, so ten clones of a 1 GiB video read as 10 GiB and take one.
So deleting a copy can free nothing
Remove one clone and the others still hold its blocks. Remove them all and a local snapshot may still keep them. That is how a disk can stay full after you delete what looked like 50 GiB.
Your Mac knows, but never says
APFS records which files share blocks and how many bytes each keeps to itself. Clonemap reads that record for every file on a drive, in one pass, and turns it into what you can act on: what is stored once, where it lives, and what is held back.
Clone families
Every copy that shares one set of blocks.
Clonemap groups the files that are clones of each other, largest saving first. Open one to see where each copy lives, what the disk really holds and what deleting them would free.
What the snapshot holds
Why deleting frees so little.
A local snapshot keeps the blocks of the files it saw. Until it goes, deleting them gives nothing back. Clonemap names the snapshot and splits your space into what it holds, what clones share and what is yours alone.
Share
Show what your drive is made of.
One card with your drive's figures and its slab, ready for a post or a message. Copy it, save it or send it from the app.
How it reads a disk
Four kinds of space, measured from metadata alone.
Exact clones
Files with one clone id and every block shared. A family of ten is stored once and counted ten times by the Finder.
Partly shared
Files that share some of their blocks: a clone edited in place, a virtual machine's disk. They save space, but not all of it.
Held by a snapshot
Bytes no clone shares that still are not private to their file. A local snapshot keeps them, so deleting the file frees nothing yet.
Yours alone
Bytes that belong to one file and nothing else. Delete it and they come back at once.
Check it against Apple's own documents
-
man getattrlistIn Terminal, on your MacThe two values Clonemap reads for every file: the clone id, and the bytes that deleting the file would free at once.
- About Apple File System Apple Developer
How a clone keeps sharing the blocks neither copy has changed.
- Apple File System Reference Apple Developer · PDF
The on-disk format. Every extent carries a reference count, and its blocks are freed when the count reaches zero.
- About Time Machine local snapshots Apple Support
How often they are taken, how long they stay, and why their space shows as available.
- View APFS snapshots in Disk Utility on Mac Apple Support
Disk Utility can list each snapshot's private size, to set beside what Clonemap reports.
Metadata only
No file is opened, changed or uploaded. The scan reads what APFS already knows.
Fast on big drives
Hundreds of thousands of files in under a minute, and the last scan opens at once.
Snapshots, named
Time Machine and macOS update snapshots, with when they were taken and what they hold.
Questions
What is an APFS clone?
A copy that shares its data blocks with the file it was copied from. macOS makes one when you duplicate a file or copy it within the same APFS drive. The two look and behave as separate files, but the drive stores the data once until one of them changes.
Why doesn't deleting files free up space on my Mac?
Two common reasons. The file may be a clone whose blocks other copies still use, or a local snapshot may still hold its blocks. Clonemap shows how much of a drive is in each case, and where.
Do Time Machine local snapshots take up space?
Yes. While a local snapshot exists it keeps the blocks of the files it covers, including the ones you deleted since. Time Machine keeps its hourly snapshots for 24 hours, and the one of its last backup until the space is needed.
Does Clonemap change or delete anything?
No. It reads file metadata and shows what it found. To act on a family, Reveal in Finder takes you to its copies.
Does it open my files or upload anything?
No file is opened. The scan reads what APFS already records about each file, on your Mac, and keeps its results there.
Why does it ask for Full Disk Access?
macOS keeps parts of the startup disk out of reach until an app is allowed in. Without it, Clonemap can still read other drives and the folders it can see, and says what it could not.
Which Macs does it run on?
Any Mac with macOS 11 Big Sur or later. It is a Universal app, native on Apple silicon and Intel.
Why is it free?
It comes from the makers of DuoBolt, which finds duplicate files and can turn them into clones. Clonemap shows how many your Mac already has.
Make more of these
DuoBolt turns real duplicates into clones.
It finds files that are byte-for-byte the same and replaces the extra copies with clones. Nothing moves, and the space comes back.
See what your Mac stores once.
Download ClonemapFree · Universal, for Apple silicon and Intel · macOS 11 or later
v1.4.4 · What's new