@deftig said: Is there no other way to make the 2013 do as I want? Or do I need to try again with a higher version of sk? with a scene of nearly 200MB, I don't see any easy way around the memory issue. Can you try installing 2016 Make version and only vray 2.0 for SU and see how it goes. I would completely uninstall vray before starting on the new install.

Solved the problem: After a while I nearly gave up on fixing the problem. But now I have found the solution. It was not a driver isue as I first thought. After deleting all the drivers and plugging in a generic computer mouse, sketchup would still not zoom when scrolling. So my next step was to question windows 8.1 and I quickly came to the answer: When you install a program that makes it possible to scroll on inactive windows (in my case: katmouse) it can cause this kind of problem. Just thought it was worth sharing.