Update 4 August 2025 - just briefly an overdue update on easier highscore support in MAME (current) for RetroArch, which I can confirm as working (done with newest MAME version 0.279)
Preparatory steps:
- Step 1: have the MAME (current) core installed
- Step 2: verify that you have the following directory: $HOME/Documents/RetroArch/system/mame - if not, then create it
- Step 3: download the entire master file from github as a zip file: https://github.com/libretro/mame and extract it
- Step 4: move the following directories into the mame directory according to Step 2: hash and plugins
- launch a game in MAME (current), enter Quick Menu, and in the Core Options/System, enable "Boot to OSD"
- Completely close RetroArch, launch it again and launch a game (horizontal monitor!) in MAME (current) -> the OSD appears
- With (TAB), jump to the General Settings of the MAME OSD, go to Plugins and activate "Hiscore Support" - don't forget to save the settings in the MAME OSD.
- After this, disable "Boot do OSD" in the Core Options and completely close RetroArch again.
- MAME has now generated the necessary ini files in $HOME/Documents/RetroArch/system/mame/ini
Still a bit clumsy, but far better than before.
Reminder: samples for very old MAME games need to be here as well - $HOME/Documents/RetroArch/system/mame/samples