Hello,
so this problem recently just popped up, first it was just the right arrow key, then the Num Pad also stopped working, just the right arrow key by the way.
I know that it is not a hardware problem because the keyboard software on windows 10 doesn't work either and also in the BIOS...
So i am running macOS Mojave i don't know if that matters but i just started playing a game Freeriderhd again and i noticed something was wrong with the right arrow key so i opened keyboard viewer to see what was detected when i pressed the right arrow key and when i pressed it and let go almost...