Thanks for the reply. I checked the location you specified and there was a GlideN64.custom.ini file in there. I checked the contents but everything was related to custom game settings and there was nothing about aspect. In the mupen64plus.cfg file there’s a GlideN64 section which does have an aspect property, however, it’s already set to Force 4:3 which obviously isn’t working. I tried each one of the settings (0-3) but they all produced the same result.