Apple has tightened up the Gatekeeper security in its latest operating system and one very visible change is that the option to allow apps from unidentified developers is no longer there.
How to fix damaged app message on macOS Sierra or later
To resolve Gatekeeper issues on macOS Sierra and unlock images and programs ( annoying image/application is damaged messages pretending you cannot open things ).
For that reason you might have to completely disable Gatekeeper checks, and to do that open your terminal and type:
sudo spctl --master-disable
**Enter your password and you’re done. Note that there are two (2) dashes before master. You might miss that while copy/pasting. So I will leave a screenshot below. I would suggest you type the command manually.
To verify that your operation was successful you need to Open Settings and verify that the Anywhere option is now visible as shown below.
Revert the Gatekeeper Settings
To enable Gatekeeper again, enter the following command (notice two dashes before ‘master’).
sudo spctl --master-enable
Use the GateKeeper Helper setting
Or we recommend to use our Helper to do that for you, the helper offer the following options:
- Disable Your GateKeeper.
- Enable Your GateKeeper.
- Allow Single App To ByPass The GateKeeper.