If you are trying to launch an application, which is not installed from App Store and the developer of the application is unidentified, then you may get an alert saying “[App name] can’t be opened because it is from an unidentified developer”. This security feature in Mac OS X is called GateKeeper, which by default blocks all the applications which are not from a verified source or from App Store.

• Mac Apps Open On Startup
• Open Mac App Store

1. When you receive a message that indicates you are prevented from opening an app from an unidentified developer, to open from Safari you can: (1) click on the download icon (the down arrow in the top right corner of Safari. (2) right click on the file to open; (3) select 'Show in Finder'; (4) in Finder, right click on the file; (5) select 'open'.
2. Open a new Finder Window; Navigate to the Download or Application you just installed to your Mac; Instead of Double-Clicking on the Icon to open, Right Click on it and choose 'Open' A Pop-Up Window will appear telling you that the Software is from an Unidentified Developer, but it will give you the option to Open it anyway.
3. Here is how you can use the Applications Folder to open apps from unknown sources: 1. Pull the Downloaded App to the Applications Folder. You can either press the control button on the keyboard and click on the App or simply right click on the application itself. Here, you will see the options.
4. For example, install the Flash plug-in for Mac OS X, or the Java runtime and browser plug-in for Mac, and neither will appear in your Applications folder. On Windows, that’s no problem — the Control Panel shows a list of all your installed programs, even ones without shortcuts.

Fix “can’t be open because it is from an unidentified developer” for a particular application without altering security settings

However, if you would like to change the security settings of your Mac (as far as app launching is concerned), then you will have to disable Gatekeeper and turn on Allow apps downloaded from to: Anywhere. How to Allow All Unknown Apps to Open on Mac Running macOS Catalina. Open Terminal on your Mac by going into Launchpad – Other. Apps that are in the Applications folder on macOS should, on principle, show up in Launchpad. All apps from the Mac App Store are installed directly to the Applications folder and other apps, those that originate from outside the Mac App Store, will ask you to move them there. It’s easy but sometimes these apps still do not appear in Launchpad.

If you want to add exception for a particular application without changing GateKeeper’s security settings, follow the steps below.

1. Here we have tried to launch “Open Office” and we got below error.
“OpenOffice” can’t be opened because it is from an unidentified developerApp photos to mac samsung s4.

2. To fix this, navigate to System Preferences > Security & Privacy.

3. There you can see below message “OpenOffice” was blocked from opening because it is not from an identified developer. Click on “Open Anyway” button, followed by “Open” in pop up. That’s it.

Now on you will able to launch this particular application (Here it’s OpenOffice) without any issue. Mac OS X will remember this exception for this particular application. But as default security settings of GateKeeper has not been altered, you will have to perform the same steps again if you get this issue for another application with unidentified developer.

You can also do the same by control-clicking (right click) on the particular application logo and then select “Open” option followed by again “Open” option to launch it anyway.

Permanent fix for all applications from unidentified developer

Mac Apps Open On Startup

For doing this you have to alter security settings in your Mac OS X, which is not a good idea as it will make your Mac less secure. Instead of doing this it’s alway recommended to allow individual applications as stated above. For permanent fix for all applications from unidentified developer follow the steps below:

1. Go to System Preferences > Security & Privacy. Click the lock to make changes and enter your account password to verify.

Open Mac App Store

2. Now set the radio button to Anywhere followed by Allow from Anywhere. This settings will be reset automatically if you don’t use this feature for 30 days.