Guild Wars 2

Everytime I open a window in front of GW2, my graphics will bug out more and more.
Basically, the lightning of certain textures will be replaced for splitseconds with a colored chess pattern (see attachments for example). The most extreme example of this happens when I open another game when GW2 is still running. If I do so, most of the graphics will bug out and I have to restart the game (see last attachment).
This bug is existing since two weaks now and I’ve already re-downloaded the gw2.dat. Does anyone know how to fix this?

You need to run the -repair command to fix the archive something has got messed up, I usually this bug when an update is rolled out, or when they release hot patches back to back, in a short space of time.

If /when you run the -repair command, if it continues to do it, check your GFX drivers, if it continues again after that, you may want to check temps etc, but hopefully the -repair will fix it.