If you installed any other release of Sun Studio software on your system, then you must install uninstall it, or install the Sun Studio 12 software in a different directory.
If you installed the Early Access release of Sun Studio 12 software, you must uninstall it before you can install the final release.
If you installed Sun Studio 10 software or Sun Studio 11 software on a Solaris 10 system, you can install Sun Studio 12 software on that system only if you specify the correct zones option when you run the Sun Studio 12 installer.
To install Sun Studio 12 software on a Solaris 10 system that has Sun Studio 10 software installed, you must install it in all zones.
To install Sun Studio 12 software on a Solaris 10 system that has Sun Studio 11 software installed, you must install it only in the zone in which you are running the installer. For more information, see Installing on a Solaris 10 1/06 OS Server With Zones