I've reflashed my Micro SD card several times now with the latest version of Recalbox and for some reason it won't show any of the Mega Drive games I move over, even the ones I know came from the previous installs of Recalbox. What's the fix for this?

Got a GPi Case, a Raspberry Pi Zero 2 and Recalbox 8.0. The Scraper doesn't work. But the bigger problem is I moved 65 megadrive roms (.md file format) into the md folder but they don't show up whereas the other games do. What's going on?