When I view the image in the library tab, nothing seems to be wrong. But when I move to the develop tab, I get this super weird effect. I have already tried reinstalling lightroom (also deleted my preferences), but without success. The only thing that changed on my laptop is a windows update, but I don't see how this could influence the program in such a way.
Try disabling GPU in Performance tab of Lr Preferences.
Thanks a lot
It's possible your OS update means that a new video card driver is also required in order for GPU to function correctly again.