Oh, also if it helps, it's Windows 10 PC, the 64 bit free Launchbox and a Matricom bluetooth controller. The issue is not with MAME but Retroarch - I don't have a MAME set to install.
I have never used any of these things on this PC, so I can't figure this out. But used RetroArch on my android box and Firestick with the same controller. No problems there at all.