Why do I get a security warning on macOS?

[pguntermann]

The user is questioning why macOS tries to prevent the application execution and tags the app as potentially harmfull.

[pguntermann]

Why does macOS prompt me about a potential security risk?

macOS only allows apple verified apps to run. Software that is not from the App Store and not signed with a verified Apple Developer ID is treated as potentially usafe. CARA is not distributed from a verified Apple developer account (it is not code-signed and notarized by Apple), so Gatekeeper may block it until you explicitly allow it.

The same applies to many open source chess engines, they are typically not signed so when CARA runs them, macOS may block them too. You may therefore need to explicitly allow both CARA and each engine you use to run on your mac.

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How to allow CARA to run

1. Try to open CARA once (e.g. double‑click or right-click and select Open). macOS may block it and show a message.
2. Open System Settings (or System Preferences) → Privacy & Security.
3. Scroll down until you see a line about the app you tried to open (e.g. "CARA was blocked").
4. Click Open Anyway and confirm if prompted.
5. Try opening CARA again; it should launch.

Once CARA is allowed, you usually do not need to repeat these steps unless you replace the app with a new download.

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Why your chess engine might be blocked too

CARA runs chess engines as separate programs on your Mac. When CARA starts an engine (e.g. Stockfish), macOS checks that engine executable as well. Most chess engines are also not signed with an Apple Developer ID, so macOS can block them too. In that case, CARA will fail to validate the engine.

So you may need to allow the engine in the same way as described above.

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Why CARA is not signed with an Apple Developer account

CARA is not code-signed or notarized by Apple for a few practical reasons:

• Release cadence vs. Apple’s process. CARA has a rapid release schedule. Apple’s notarization and review process adds delay for every new release build. Submitting each release for notarization does not fit well with shipping fixes and features quickly.

• Ongoing cost and overhead. Signing and notarizing macOS builds require an Apple Developer Program membership (paid annually) and extra tooling and steps for every release. For an open-source project maintained voluntarily, this is not reasonable.

As the project is open source, users can verify its safety at any time.