@alvinicoogh I'm not sure what might be going on, and I don't have an ipac2 to test, so I recommend you run some tests in order to rule out the possibilities:Is it possible for you to test with a common keyboard, without IPAC2? If yes, test. Test with another console besides MAME to check if the incompatibility is MAME specific or not Test with another key combination, avoiding ALT, CTRL, SHIFT, etc.: test only with letters or numbers Test with player 1 only overload Test without folder overload
They are just tests, but their results can lead to the solution.