How to Bypass the macOS Gatekeeper to Open Unidentified Apps Safely

To protect users from malware, Apple introduced Gatekeeper. By default, macOS will only allow you to open applications downloaded from the official Mac App Store or applications created by developers who possess an active Apple Developer ID certificate. If you download an open-source tool, an older indie game, or an internally developed corporate app that lacks this expensive certificate, macOS will block it, displaying a message that the app “cannot be opened because the developer cannot be verified.”

Method 1: The Context Menu Bypass (Recommended)

The safest way to bypass Gatekeeper is on a per-application basis. This method tells macOS that you acknowledge the risk for this specific app, while keeping Gatekeeper fully active for everything else you download.

1. Open Finder and locate the application that macOS refused to open (usually in your Applications or Downloads folder).
2. Do not double-click the app. Instead, right-click (or Control-click) on the application icon.
3. From the context menu that appears, select Open.
4. A new warning dialog box will appear. Unlike the previous error message, this box will include an Open button.
5. Click Open.

macOS will launch the app and automatically add it to an internal whitelist. You can now double-click the app normally in the future, and Gatekeeper will ignore it.

Method 2: The System Settings Bypass

If you tried double-clicking the app and were presented with the error message, macOS actually logs that failure in System Settings, giving you a temporary window to override it.

1. Click the Apple menu () and select System Settings (or System Preferences on older OS versions).
2. Navigate to Privacy & Security.
3. Scroll down to the “Security” section.
4. You should see a message stating that the app was blocked from use because it is not from an identified developer.
5. Click the Open Anyway button next to this message. You may be prompted to enter your Mac login password or use Touch ID to confirm the action.

Method 3: Removing the Quarantine Attribute (Advanced)

When you download a file from the internet via a web browser (like Safari or Chrome), macOS attaches an extended attribute to the file called com.apple.quarantine. This attribute is what triggers Gatekeeper to inspect the app. If the app is corrupt or you need to launch a command-line binary that lacks a graphical interface to right-click on, you can strip this attribute using the Terminal.

1. Open the Terminal application (found in Applications > Utilities).
2. Type the following command, ensuring you leave a space at the very end:
   xattr -d com.apple.quarantine
3. Drag and drop the blocked application from Finder directly into the Terminal window. This will automatically fill in the correct file path.
4. Press Enter.

The quarantine attribute is instantly deleted. The next time you open the app, macOS will treat it as if it was created locally on your computer, bypassing Gatekeeper entirely. Use this command-line method with extreme caution, as it completely circumvents macOS’s primary malware defense mechanism for that specific file.