I recently needed to download an app from a developer on the internet that I had used on other (Windows machines). However on my Mac when I tried to run it I got the below error:

I checked Privacy and Security from Settings but the only options shown were ‘Allow applications from App Store’ or ‘App Store and identified developers’. I could click the ‘Open Anyway’ but I also had an application that called multiple other applications to install and doing this for each component would be time consuming.

After a good Google I found that from Mac OS Sierra, Apple introduced an OS application called Gatekeeper, that protects from downloading and running files from unknown sources. This is hidden in the background of the OS and not something we can switch off from the GUI part of the OS. To turn off this feature follow the below:

DISCLAIMER: It is not recommended to turn off the Gatekeeper feature unless you are sure that the app you are running\installing is from a source you trust. I would recommend re-enabling this feature once you have finished with the app\installer.

Open Terminal and enter the following command

sudo spctl --master-disable

Once you press Enter , you should be prompted for your Mac password. Enter it and press Enter on the keyboard.

If it works then you should go back to the prompt.

Now when we run the app we can click to open it.

To re-enable it just use the following command in terminal

sudo spctl --master-enable