For the current GRAPHISOFT products the default Mac App Store and identified developers is a good choice, but older versions and the protection key drivers may not be installed using this security option. With those settings you can control which applications are allowed to be installed on the computer. Mac App Store and identified developers.Gatekeeper is built in Security option in OS X Mountain Lion that prevents you from running potentially harmful applications. If migrating to a new computer please see Transferring data between computers with Apple's Migration Assistant topic of this article below. Test ARCHICAD and the BIM Server (see BIM Server doesn't start after migrating to Mountain Lion topic of this article below).
Install all current operating system updates and ARCHICAD updates prior to the upgrade.Allow yourself enough time for the upgrade, do not upgrade the OS close to a deadline.Return all borrowed licenses before upgrading the OS.Back up all of your ARCHICAD / BIM Server specific data before upgrading the operating system.Study this article for any known issues, difficulties.
PlotFlow, which is also a PPC application, won't work either (it is no longer part of the ARCHICAD package from AC15). As a consequence, ARCHICAD10 will be the oldest version running on OS 10.8 Mountain Lion and files created with ARCHICAD 6.0 or older will not open on OS 10.8.