@giovanni11 said in world rally 2 gaelco dual screen problem:

After starting mame I pressed the TAB key and this menu opens, clicking on "dip switches" I have the possibility to change monitors 1/2, but I tried and selecting "monior 1, then the emulator always restarts with two screens

Well, then I'm afraid I can't help you. I know nothing about MAME64UI on pc. I play the game using FBNeo on a Raspberry Pi 3 and the monitor setting does pertain in that.

I do believe there's an FBNeo version for Windows, but I also don't know anything specific about that.