Support
Sunflower is free. If something here does not answer your question, there is a way to get in touch at the bottom of the page.
What you need
- macOS 15 or later
- A Mac with Apple silicon
- Full Disk Access, if you want the total to include Mail, Time Machine backups and other users' files. The app runs without it.
Installing it
The download is a disk image. Open it and drag Sunflower to the Applications folder beside it, then eject the image. Apple has notarized the app, so it opens the first time without a warning about an unidentified developer.
Getting started
Open Sunflower and it shows the disks attached to your Mac, each with how full it is. Pick one and the scan begins. It takes a few minutes on a full disk, and you can stop it at any point and keep what it found.
When it finishes you get a ring: the volume in the middle, its folders around it, and two more levels beneath those. Click a folder to see what is inside it, sorted largest first. Click one of those to go there.
The switcher in the top bar picks how you see the folder you are in: rings, a treemap, a plain list, or one answer about everything beneath it: what is largest, what kind of thing it is, or what has not changed in years.
Granting Full Disk Access
Open System Settings, go to Privacy & Security, then Full Disk Access, and turn Sunflower on. The app has a button that takes you straight there, in Settings and on the banner it shows when it could not read everything.
Sunflower notices the change the next time you bring it to the front. Run a scan again and the total will include what it could not reach before.
Questions
Why is the total smaller than what macOS says I have used?
Because something was unreadable. macOS keeps folders like Mail, Time Machine backups and other users' files behind Full Disk Access, and without that permission Sunflower cannot measure them. When that happens the app says so and tells you how much it could not account for.
I turned Full Disk Access on and it still says it cannot see everything.
macOS attaches the permission to one copy of the app, so an entry left over from an older copy does not carry across. Remove Sunflower from the Full Disk Access list with the minus button, add the copy in your Applications folder with the plus button, then quit the app and open it again. A running app keeps the access it started with, so the relaunch is the step to remember.
What is System Data, and why is it so big?
It is the name macOS gives to everything it does not sort into another category: caches, logs, derived data, local snapshots, device backups. Sunflower's System Data screen splits that one number into named rows and says what each one is, so you can decide about them one at a time.
Why do some files show as zero bytes?
They live only in iCloud. A file you have not downloaded takes no space on your Mac, so zero is the true answer. Sunflower will not download one in order to give it a bigger number.
How do I find what is worth deleting?
Beside the rings, treemap and list, the top bar offers three questions you can ask of whatever folder you are in. Largest lists the biggest files and bundles beneath it. Kinds groups every byte by what it is: videos, disk images, archives, installers, build folders and so on, each with a line about what deleting it means. Untouched shows what has not changed in one, two or five years, with the date it last changed. All three narrow as you drill in, and a file found in any of them deletes the same way as one found in the rings.
Where do deleted files go?
The Trash, and they stay there until you empty it. Before removing anything the app shows a confirmation that lists what is going and how much it frees.
Can Sunflower delete something macOS needs?
No. It refuses to remove system paths, it says so on the item when you select one, and there is no setting that changes it.
Does it scan automatically when I open it?
Not unless you ask it to. Opening the app reads a disk name and a capacity and stops there. If you would rather it started on its own, there is a switch for that in Settings.
Can I stop a scan partway?
Yes, and you keep what it found up to that point.
Does it send anything over the internet?
No. Sunflower makes no network connections at all. See the privacy policy for the detail.
Who makes Sunflower
Gjorge Karakabakov, an independent Mac developer, writes and maintains Sunflower. He built it to find out what his own Mac's System Data was made of, after the standard advice (clear some caches, restart, hope) freed nothing. This site explains what the app does, and you can check every claim on it against the app.
Get in touch
For anything not covered here, including bug reports and feature requests, contact the developer through karakabakov.com.
When reporting a problem it helps to say which version of macOS you are on, which disk you were scanning, and what you were doing when it went wrong.