HE Instructor Knowledge Base URL: http://cmg.screenstepslive.com/s/MacmillanMedia/m/FAQs/l/475420-what-can-i-do-if-the-diploma-installer-won-t-open-on-mac-os-x
What can I do if the Diploma Installer won't open on Mac OS X?
If you attempt to install Diploma 6.72 but receive an error that the developer cannot be confirmed and therefore cannot be installed, follow the below steps to solve this problem.
An alternative method to fix this problem is to change the Gatekeeper Settings altogether. Choose "Security & Privacy" in System Preferences and change the "allow apps download from.." button to "anywhere."