Fix the macOS Error: App Is Damaged and Cannot Be Opened

You download Clash Verge Rev, drag it into Applications, double-click — and macOS announces the app "is damaged and can't be opened", suggesting you move it to the Bin. The wording is alarming and almost always wrong: the file is fine. What you are seeing is Gatekeeper, Apple's app-screening layer, reacting to software distributed outside the App Store without Apple's notarization stamp.

Open-source apps hit this constantly, and the fix takes under a minute. Below are three working methods, from the point-and-click route to the terminal one-liner, plus the safety context you should have before using any of them.

Why macOS says the app is damaged

Every file downloaded through a browser gets tagged with a quarantine attribute (com.apple.quarantine). On first launch, Gatekeeper inspects tagged apps: those signed and notarized by Apple open normally, while apps without that paper trail trigger either "unidentified developer" or the harsher "damaged" dialog, depending on macOS version and how the app was packaged. Community-built software like Clash Verge Rev is exactly the kind of project that trips this check — the message reflects missing notarization, not actual file corruption.

Method 1: allow it in Privacy & Security

1. Double-click the app once so macOS registers the block, and dismiss the dialog.
2. Open System Settings → Privacy & Security and scroll to the Security section.
3. Find the line saying the app was blocked, and click Open Anyway.
4. Confirm in the dialog that follows (macOS may ask for your password or fingerprint).

The exact wording shifts between macOS versions, but the flow — trigger the block, then approve it in settings — has stayed the same for years. Approval is remembered, so this is a one-time step per app version.

Method 2: remove the quarantine attribute in Terminal

The direct approach is deleting the quarantine tag itself:

xattr -dr com.apple.quarantine "/Applications/Clash Verge.app"

-d deletes the attribute, -r applies it recursively to everything inside the app bundle. Adjust the path for other apps — the same command unblocks a downloaded mihomo binary, for example. After it runs, the app opens with no dialog at all. If Terminal reports "No such xattr", the tag was already gone; the app should simply open.

Method 3: right-click and Open

On some macOS versions, Control-clicking the app in Finder and choosing Open presents a dialog with an extra Open button that the plain double-click hides. It tends to help with the "unidentified developer" variant more than the "damaged" one — worth ten seconds before reaching for the other methods.

If it still will not open

When the app launches and immediately dies, or the dialog returns after a successful bypass, quarantine is no longer the issue. The usual remaining causes: a build for the wrong chip — check whether you grabbed the Intel or Apple Silicon package, explained in the architecture guide — or a genuinely corrupted download, fixed by re-downloading. The full setup flow, including these prompts in context, is in the macOS install guide; for crashes after a successful launch, start with the common errors guide instead.

Frequently asked questions

Is removing the quarantine attribute safe?

The command only removes the "downloaded from the internet" marker from that one app, skipping its first-launch screening. It does not weaken system protection generally. The safety decision happens earlier — when you choose where to download from. Verified source, low risk; unknown source, do not bypass anything.

Will the warning come back after updates?

Yes, usually. A newly downloaded version is a new quarantined file, so expect to repeat Method 1 or 2 after manual updates. In-app updaters typically avoid re-triggering it.

Why does Apple not just trust open-source apps?

Notarization requires a paid developer account and Apple's signing pipeline. Volunteer projects often skip that overhead, so Gatekeeper treats their builds as unknown — a policy trade-off, not a judgment on the software's quality.