Disabling Gatekeeper From the Apple menu, open the "System Preferences" application. Click on Security & Privacy > General tab. If the lock in the left-hand corner is locked, click on it, then enter your Mac's username and password. This may not be required. Click "Anywhere" under "Allow applications downloaded from:". If you followed Step 3, please click the lock in the left-hand corner to return it to its locked state. Close "System Preferences".