Hi,
So I've been using PS CS6 to work with concept art for a while now, and since I formated my PC, I've been having some issues with the OpenGL, it seems that my photoshop doesn't recognize it or something (or my graphic card, I'm not sure). Thing is; sometimes my PS starts smoothly, with everything working just fine, but when I close it and re-open it, some funcions like the canvas rotation or propper anti-aliasing on broken zoom values (like 33,33%) just stop working ("could not complete your request because it only works with OPENGL enabled document windows"). Right now I'm using windows 7, 64 bits, 16GB Ram and Intel(R) HD Graphics 4000. I've tried reinstalling the drivers multiple times but it just goes the same: It works, but it's still VERY instable (like, for each 20 times I open my PS CS6, only one is actually working properly).