I've only started working with the OSX version. Thor, I move in and out of Poser 4 while rendering and have never had any problems. Don't know why you have encountered them. I chose to switch out my most used products to P5. Very simple drag and drop from one runtime folder to the other. I had talked with Will Duprwho had told me P5 seemed to like V3 in the P5 Runtime. So I decided to just move my favorite things there. No problems so far. Injections working fine. I agree, it is an annoying oversight not to have undo on the parameter dials. All operations I have tried so far (the regular stuff you can mostly do in P4) are fine and fast. I'll check out the P5 specific stuff as I go along. Material room for renders has checked out fine. Though the one thing I do not like is if you choose to save, for instance, a skin node to the Materials Library, it insists on saving any loaded map even if the node is not connected. It's nice not to have to start up Classic to go into P5, though DAZ's installers are built to start up Classic in the installation problem. Also, I don't know that there is a OSX version of Maconverter (will have to check). So I'm not out of the Classic woods yet. I've worked with the PC version, so was familiar with the Firefly engine and have always thought it was very nice. Materials and cloth room were the two things I wanted access to and now I have it. Cris