macOS 11+ · Notarized by Apple

What’s actually in System Data?

Lucid Disk scans your Mac on-device and tells you, in plain English, what every cache, duplicate and old backup is — and whether it comes back if you remove it.

Download for MacBuy a licence — $9.99

Free to download. A $9.99 one-time licence for 2 Macs unlocks scanning.

Nothing removed without youUndo any cleanupFiles never leave your Mac
Scout found 66.4 GB
Scout is your scan dog. Sorted by how safe each one is to clear.
Developer caches
Xcode DerivedData, CocoaPods, npm, Homebrew — rebuild on their own
41.2 GB
Browser & Mail
Safari and Chrome caches, Mail attachments — review first
15.8 GB
Old device backups
iPhone backup — device not seen since March 2024
9.4 GB
41.2 GB selected · all rebuild automatically
Move 41.2 GB to Trash
100% on-device
Scanning, hashing and matching run locally
0 file paths
ever sent anywhere — only the licence and update checks go online
$9.99 once
Two Macs. No account, no renewal
65 GB
found on the developer’s own Mac
How it works

Four steps. You make every call.

01 — Scan
Measuring ~/Library …
48.9 GB measured
Checks where Finder can’t see
Developer caches, browser data, Mail downloads and old device backups — one pass over your disk, in seconds.
02 — Explain
CocoaPods cache · 9.1 GB
Rebuilds on its own
iPhone backup · 9.4 GB
Won’t come back
Plain English, not paths
Every result says what it is and whether it comes back on its own.
03 — Select
Xcode DerivedData 18.4
npm + Homebrew 13.7
Mail attachments 5.2
Only safe items pre-ticked
Caches that rebuild themselves start selected. Everything else waits for you.
04 — Clear
32.1 GB
moved to the Trash · Undo puts it all back
Undo, or free it now
Everything goes to the Trash first. “Free space now” empties just this cleanup, and asks before it does — that part can’t be undone. Protected system paths are always refused.
Two views, one scan

Just want space back? Simple. Want to dig? Explore.

Simple gives a yes/no per category. Explore maps the whole disk so you can trace every gigabyte. Both read the same scan, so the numbers always match.

Try the switch in the window above.

What it finds

“System Data” isn’t one thing. It’s all of this, unlabeled.

On every Mac
Browser & Mail
Safari cache6.4 GB
Mail attachments5.2 GB
Chrome cache4.2 GB
Caches rebuild as you browse. Mail attachments are listed one by one and re-download from the server if they are still there, so you decide what goes.
Developer caches
If you write code: Xcode, npm, Homebrew and CocoaPods caches, and project folders like node_modules. Docker is reported, never touched.
Only shown when found
Duplicates & old backups
Content-hash duplicates, not filename guesses. iPhone and iPad backups from devices you no longer own.
10–30 GB per old backup
Why Lucid Disk

A cleaner that explains itself — and doesn’t bill you yearly.

Lucid DiskSubscription cleanersBy hand (Finder + Terminal)
Price$9.99 onceYearly planFree, costs an afternoon
Says what each item isYes, plain EnglishCategory levelIf you know the paths
Developer cachesBuilt for themPartialManual
Account / data leaves MacNone / neverUsually an accountNone
Pricing

One price. Yours to keep.

No subscription to remember to cancel. Buy once, use it on two Macs, and get every 1.x update.

$9.99one-time
Stable price, not a launch discount.
  • Every category, developer caches to duplicates
  • Activates on 2 Macs, transferable
  • Free updates for all of 1.x
Buy licence — $9.99Download the app
The licence key arrives by email and is needed before the first scan — there is no free scan mode, so if it isn’t right for you, email us within 7 days for a full refund. macOS 11 or later · Apple silicon and Intel.

Questions

Why does it need Full Disk Access?

To read the folders macOS hides from apps. It is used to report sizes only — nothing is touched until you select it and confirm.

Can it delete something I still need?

Not on its own. Only caches that rebuild themselves are pre-selected, and nothing moves until you confirm. Everything goes to the Trash first, and Undo puts the whole cleanup back. Protected system paths are re-checked before anything moves, and refused.

What does “Free space now” do?

Moving files to the Trash does not give space back until the Trash is emptied. “Free space now” empties just that cleanup — anything else in your Trash stays put. It asks first, because that part cannot be undone.

Does it work offline?

Yes. Activation needs the internet once. After that the app checks your licence when it starts, and keeps working for 7 days without a connection.

How many Macs does one licence cover?

Two. It can be deactivated on one Mac and moved to another.

How much is hiding in yours?

Scout will tell you in under a minute.

Download for Mac