Imagine you’ve downloaded software from the web and entered your admin password correctly, yet you can’t install the program because it’s supposedly from an unidentified developer. What do you do?
If you encounter this message, chances are you’ve encountered a security feature in Mountain Lion 10.8. Fortunately, there is simple workaround that will allow you to complete the installation of this application and others like it in the future.
Open System Preferences, select the Security & Privacy icon, then click the General tab near the top of the menu. In the subsection entitled, “Allow applications downloaded from,” change the radio button from “Mac App Store and identified developers” to “Anywhere.” You may need to enter your admin password to open the lock in the lower left corner that will you to make changes. Now run the installer again.