Opening Ditherlab on macOS

Ditherlab is free and open-source, so it isn't signed with a paid Apple certificate. macOS blocks unsigned apps from outside the App Store on first launch — on macOS 15 the message reads "can't be opened… this software needs to be updated." Nothing is wrong with the app; this is Apple's standard warning. Here's how to open it — you only do this once.

1. Move it to Applications

In the download window that opens from the .dmg, drag the Ditherlab icon onto the Applications folder.

2. Approve it in Settings

1. Open Ditherlab from Applications once. You'll see the block message — click Done.
2. Open System Settings → Privacy & Security.
3. Scroll down to Security. You'll see "Ditherlab was blocked…" with an Open Anyway button — click it and enter your password.
4. Open Ditherlab again and click Open. Done for good.

Or, the one-command way

If no Open Anyway button appears, open the Terminal app and paste this, then press Return:

Then open Ditherlab normally. This removes the "downloaded from the internet" flag so macOS stops blocking it.

Prefer to verify before trusting it? Ditherlab runs fully offline and never sends your images anywhere — the complete source code is on GitHub.