Bristol_Jonesey
The only time it makes sense to not have previous version(s) installed is on a brand new clean build, and even then, there are times when a partial install is required in order to use plugs no longer shipped with a latest version, such as the Lexicon Pantheon.
Actually here's the reason: I have a laptop that I use only for live sound and recording. After recording, Sonar projects are transferred off to my desktop DAW for editing/mixing. (I.e., there are no 'old' Sonar projects ever on this machine.) Laptop currently has 8.5 and X1 installed. It also has an SSD of limited size. Was thinking about installing and using X2 for recording, and maybe removing at least 8.5 from the laptop to save SSD space.
None of this is critical, was just wondering how easy it would be. Because my current setup is very stable, I hesitate to change it. One of these days when I'm feeling brave, I'll remove 8.5 and X1, and just do a clean install of X2 on the laptop.
Thanks for the input everyone..... I'll try to remember Google next time.