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OS X Mountain Lion: Application Signing
By default, Mac OS X Mountain Lion disables the ability to run applications which are not signed, the idea being to prevent hackers from persuading you to run a nefarious application.
This is an excellent security precaution, but also a headache until all apps are signed (and some never will be).
When an application is not signed as per the system preferences (see below), you will see a dialog like the following:

There are two ways to allow an application to run—
Allowing an application to run — context menu
Right-click or control click on the application, choosing Open:

A dialog then appears to confirm that you want to open the app:

Allowing an application to run — system prefs
Use some care here— be certain of the origin of the application!
The quick way is to use a contextual menu: right-click (control-click) the application.
To allow the application to run:
- Temporarily choose “Anywhere”.
- Run the application.
- Change security back to previous setting.
Once the application has run, it is “approved” and these steps will not be necessary again for that particular application.
