I would like to know if it is permissible for a member to do the following. Most of us have 1.23b and 1.5.1. I have had 1.5.1 stop working on three separate occasions now. I have 1.23b on a different drive and it still works. Will there be any conflict between the two versions, or should I put the two different versions on different computers?
DeeVee.
Hello Joe!!
I haven’t both of version but for me (from my computer experience!) is the best if you install the different version of program into different locations (different folder or hard disk!) 
Hope that is helpful for u !!! 
Thanks that is how I have it at the moment.
DeeVee.
Joe.
According to what aurick said, the “right” folder for 1.5x is “ZBrushOneFive”, exactly this way. Well: he was/is right, no doubt!!
1.23b sits on another partition and takes a loooong rest !