So that you can install some applications on Mac, you need to know how to deactivate Gatekeeper on macOS. Otherwise, when you want to install some applications, the message "App cannot be opened because it is from an unidentified developer."
Before you see how you can disable Gatekeeper on macOS, it is very important to know what this feature means and what it helps.
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What is a Gatekeeper on macOS?
Gatekeeper is a security function integrated into the operating system macOS, starting with the version OS X Mountain Lion (10.8), which helps protect users against malware applications and other malicious programs. Basically, this function controls which applications are allowed to be installed and to be opened on one Mac.
By default, Gatekeeper is configured to allow installing and opening only applications downloaded from App Store or of those from identified developers and check by Apple.
If you try to install an application from a developer not identified by Apple, the running of the application installation will be stopped with the message "App cannot be opened because it is from an unidentified developer."
Gatekeeper it does not protect you from malware applications 100%, but it helps a lot for users who are not very technical and who can download applications from the Internet that could be dangerous for the operating system. Gatekeeper prevent you from accidentally installing applications that could affect security Mac.
How to disable Gatekeeper on macOS?
Most of the time I don't recommend disabling security features of the operating system, but there are also situations in which if you need to install an application from outside the App Store, or which is created by an unverified developer Appledisabling Gatekeeper is required.
In our example, we will take the application called "App.dmg” which is created by a “unidentified developer” and which Gatekeeper blocks it.
When we try to open the file to install the application "App.dmg” we receive the message: “App.dmg” cannot be opened because it is from an unidentified developer. With the addition of ca macOS cannot check if this application contains malware.
If this message appears when you try to install an application, you have two methods at hand.
Method 1: Open the application blocked by Gatekeeper
You can open the blocked application from: System Settings → Privacy & Security.
Under "Security” you will find the option through which you can open the application blocked by Gatekeeper. "Open Anyway".
"By opening this app, you will be overriding system security which can expose your computer and personal information to malware that may harm your Mac or compromise your privacy.” – Click “Open".
The application “App.dmg” will open, but if it has several installation processes, it is possible that it will still be blocked by Gatekeeper.
Method 2: Disable Gatekeeper and allows installation from multiple sources
The safest method to be able to install applications from any source, not only from the App Store and from verified developers, is to disable Gatekeeper. Thus you will be able to choose for yourself if you want to allow the installation of applications on macOS, and from other sources. "Anywhere".
Open Terminal on macOS and execute the command line (enter the user password for the line to be executed):
sudo spctl --master-disableYou go back to "Privacy & Security" and activate the new option "Anywhere".
Now you can install any application on macOS, even if it is not from the App Store or from a developer identified and verified by Apple.
You can activate the Gatekeeper protection on the spot through the command line:
sudo spctl --master-enableThere are scenarios in which the applications still cannot be installed. "App is damaged and can’t be opened".
In this scenario, you must be very careful that the installation of that application does not compromise the integrity of the operating system. If you still want to install an application when the error message appears: “App is damaged and can’t be opened", you can remove the extended attributes of that application. Including those attributes that can block the running of the application for security reasons.
Run in Terminal, the following command line:
xattr -cr /full/path/Application.appOf course, change the path and the name of the application in the command above. (Type: drag with drag&drop application in Terminal, after you have written the command line).
