At this month’s busy SEAL meeting we only had time for one question:
Q. When I attempt to start Open Office after downloading it from the Internet, I get the message “Open Office can’t be opened because it is from an unidentified developer” and it will not start.
A. This message comes from Gatekeeper, the anti-malware feature that Apple introduced in Mac OS 10.8 Mountain Lion. By default, Gatekeeper only allows apps that have been downloaded from the Mac App Store and those that come from identified developers to open. Apps that come from developers who have not registered with Apple and signed their app with a developer ID (i.e. the developer is unidentified) display the message above when double clicked and will not open.
In this case, Open Office is not signed with an Apple developer ID so it is prevented from opening by Gatekeeper. If you are confident that you have downloaded a genuine copy of Open Office from the official web site then you can override Gatekeeper and let Open Office start. To do this:
1, Control-click or right click on the Open Office icon.
2. Select Open from the top of the context menu that appears.
3. Click Open in the dialog box that warns you that Open Office is unidentified.
4. If prompted, enter your administrator user name and password.
OS X will record that you trust the app and from then on you can start it normally without warnings.
Apple’s About Gatekeeper support article explains the system in more detail and includes information about the options available for it in System Preferences.