I use Photoshop on my PC and it's never shown any instability. I'm not even sure that what meant. How would it be unstable? It works beautifully and always has. I had it on my old, less powerful computer, an then moved it to my new one, and it worked perfectly on both machines. It's never crashed and it's never done anything flaky. Also, I've never understood why anyone would need to have two programs running at the same time. How does running Vue and Poser at the same time benefit the artist? It seems to me that you can only do things in one at a time anyway, so how would that be better? Just wondering. Melanie