Have loaded 4.3.1 on my Power mac version 10.4.1 Tiger. Also, have 4.2.1 on same machine. Should I delete 4.2.1 or does it matter? Reason for asking. When I create a new effect in 4.3 I save it obviously, but when I relaunch. the computer launches 4.2.1? The Icon on the desktop is just a blank script. Still works properly, but just a blank script.
Sounds to me like the icon on the desktop needs to be repaired as it's still pointing to the old version. Here's what to do. First delete the old icon from the Desktop. Then go to the directory where the application resides and create a new alias to the app. Then drag this alias onto the desktop. That should sort out the problem for you.
And it should be okay for you to either delete the older version of the application or to leave it there if you wish. This should not affect the performance of the system.