By default, Gatekeeper is set to ‘Mac App Store and identified developers.’ This means that a Mac will only run applications you have downloaded from the App Store or applications that have been signed with an official Apple Developer ID.
Here's how to disable Mac Gatekeeper
1. Launch System Preferences from the Apple menu
2. Choose “Security & Privacy” and then click the “General” tab, followed by clicking the lock icon in the corner to unlock the settings
3. Look for “Allow applications downloaded from:” and choose “Anywhere”
4. Accept the security warning and allow
5. You can now launch any app from any location or developer.
Very Well Explained Chris! (Y)
Thank you for sharing this post here Chris.