‘App is Damaged’ Error on macOS: How to Fix and Bypass

What Does the "App Is Damaged" Error Mean on macOS

When attempting to launch an application on macOS, you may see a dialog box with the message: "Application Name is damaged and can't be opened. You should move it to the Trash." This is a system warning from Gatekeeper—a macOS security component that checks whether an app is signed by a trusted developer and hasn't been altered since it was signed.

The error occurs before the program actually launches, at the operating system level. macOS blocks execution even if the file is not physically damaged but doesn't meet security requirements (for example, if it lacks an Apple digital signature or the developer's certificate has expired).

Common Causes

The "App Is Damaged" error is usually caused by one of the following:

1. The app is unsigned by the developer. Many utilities or older programs lack a digital signature, which conflicts with Gatekeeper policy.
2. The digital signature is invalid or expired. The developer's certificate may have lapsed, or the app was modified after signing (e.g., by antivirus software or during archive extraction).
3. The file was corrupted during download. A network failure or a bad archive can alter the binary file.
4. Aggressive security settings. In macOS Catalina and later, Gatekeeper by default only allows apps from the App Store and those signed by developers. Apps from unknown sources are blocked.
5. Conflict with antivirus or security software. Some security programs may "clean" signature metadata, making the app appear "damaged" to Gatekeeper.
6. Outdated macOS version. On older systems (pre-Catalina), Gatekeeper is less strict, but after updating the OS, previously working apps may become blocked.

Method 1: Allow Launch via Finder Context Menu (Simplest)

This method works for apps that Gatekeeper blocks but that have no obvious file corruption.

1. Open Finder and navigate to the Applications folder (or wherever the .app file is saved).
2. Locate the problematic app, Ctrl+click (or right-click) on its icon.
3. In the menu that appears, select "Open" (do not double-click!).
4. A dialog will appear: "Are you sure you want to open...?" — click "Open".
5. The app will be added to Gatekeeper's exceptions and will henceforth launch with a normal double-click.

⚠️ Important: This option is only available if the app is signed but not trusted. If there is no signature at all, the "Open" option in the context menu may be absent.

Method 2: Change Security Settings in System Preferences

macOS sometimes offers a temporary override via the security pane after a failed launch attempt.

1. Try to launch the app normally (double-click) — the error will appear.
2. Open System Preferences → Security & Privacy → General tab.
3. At the bottom of the window, below the block message, a button "Open Anyway" may appear. Click it.
4. Confirm the action in the dialog. The app will then launch.

💡 Tip: The button appears only after the first launch attempt of the blocked app in the current session. If you restart your Mac, you'll need to attempt to launch the app again to activate the button.

Method 3: Use Terminal to Force-Add to Whitelist (Advanced)

If the previous methods didn't work (e.g., the app is completely unsigned), you can manually add it to the trusted list using the spctl command.

1. Launch Terminal (from Applications → Utilities).
2. Enter the command, replacing AppName.app with the actual file name:

   sudo spctl --add --label "Whitelist" /Applications/AppName.app
   

3. Enter your administrator password (characters won't be displayed — this is normal).
4. After successful execution, the app will be permitted to run.

⚠️ Important:

• Ensure the path to the app is correct. If the app is in a different folder, provide the full path (e.g., ~/Downloads/MyApp.app).
• Using sudo grants the app full system access. Only add programs from verified sources to the whitelist.
• To remove an app from the whitelist, run: sudo spctl --remove /Applications/AppName.app.

Method 4: Reinstall the App with Integrity Verification

If the app was corrupted during download or installation, a clean reinstall will help.

1. Remove the current version: drag the .app file from the Applications folder to the Trash and empty it.
2. Download the app again from the developer's official website. Avoid third-party repositories.
3. Verify the checksum (if the developer provides one):
   • In Terminal, run:

     shasum -a 256 /path/to/downloaded/file.dmg
     

   • Compare the output with the hash on the website. If they don't match — the file is corrupted; download it again.
4. Install the app by dragging the icon to the Applications folder (for .dmg) or running the installer (.pkg).
5. Try to launch it. If the error persists, return to Method 1 or 2.

Method 5: Temporarily Disable Gatekeeper (Not Recommended)

This method reduces system security and should only be used as a last resort for critically important software you trust.

1. Open Terminal.
2. Run the command:

   sudo spctl --master-disable
   

3. Enter your administrator password.
4. Now in System Preferences → Security & Privacy → General, the option "Allow apps downloaded from: Anywhere" will appear — enable it.
5. Launch the desired app.
6. After use, revert the settings:

   sudo spctl --master-enable
   

⚠️ Critically important: Do not leave Gatekeeper disabled permanently. This makes your Mac vulnerable to malware.

Preventing the Error in the Future

To minimize the risk of the "App Is Damaged" error recurring:

• Download only from developers' official websites. Avoid torrent trackers and dubious mirrors.
• Check digital signatures. In Finder, you can right-click the .app file → "Show Package Contents" → Contents → _CodeSignature. If the folder is absent, there is no signature.
• Update macOS. Newer system versions improve Gatekeeper's operation and add trusted certificates.
• For developers: sign your apps with an Apple Developer ID. This ensures Gatekeeper will allow them.
• Do not disable Gatekeeper permanently. Use exceptions only for specific, verified programs.

Additional Options for Developers and IT Specialists

If you are a developer or system administrator encountering this error across multiple Macs, consider:

• Deployment via MDM. In a corporate environment, use Mobile Device Management (e.g., Jamf, Kandji) to automatically trust applications.
• Create a custom certificate. For internal tools, you can create a self-signed certificate and add it to trusted via Keychain Access.
• Use xattr to remove attributes. Sometimes the error is caused by the com.apple.quarantine attribute. Remove it:

  xattr -rd com.apple.quarantine /Applications/AppName.app
  

  Then try launching again. Caution: this does not verify the signature; it only removes quarantine. Use with care.

Frequently Asked Questions (FAQ)

Can Gatekeeper's verification be completely disabled?
Yes, via sudo spctl --master-disable, but this is highly discouraged. It's better to add only necessary apps to the whitelist.

Why does the app still not launch after bypassing via Terminal?
The file may be physically corrupted or missing libraries. Check the app in Console.app for loading errors (e.g., dyld: Library not loaded).

How to check if an app is signed?
In Terminal, run: codesign -dv --verbose=4 /Applications/AppName.app. If the output contains code object is not signed at all — there is no signature.

What to do if an App Store app also fails to launch?
This is atypical. Try signing out of your Apple ID and back in, update macOS, reinstall the app via the App Store. If the problem persists — contact Apple Support.