There's nothing in RetroPie that enabled or disbables writing on the scard. SD card turning read-only is sometimes a sign of a damaged card.

Backup your data - see Option 2 of how you can backup - and re-install. Scraped data is kept in one of these places: the ROMs folder (if you've used an external scraper). the \\retropie\configs\emulationstations\downloaded_images folder, if you've used only the EmulationStation internal scraper(s). So if you take the advice in the docs and back-up your ROMs and configs folders, you should be able to keep your games and scraped data.

@mitu I tried that link but I don't have a C:/Users/Herb Fargus/ folder on my Windows 10 installation. Do you think Herb would be willing to swing by and log into my machine sometime soon? :^()

ALl I had to do was move the NV files as well as all emulator named folders under roms\arcade over and all is great!

@likethereindeer Thanks, but I meant at the beginning of the title so that it reads "[SOLVED] Prep a 128GB Card on Mac". So everyone can see in the topic list that the thread has already been solved. Potential helpers can then look for other problems to solve, and people with the same problem as yours know there may be a solution to be found here. :)

Great, thank you for the quick response I appreciate it!

Thanks! Deleting the .cfg files did it. I was dumb and left out the fact that, though it was a clean install of retropie, I coped my roms dir over from another machine. I either forgot or never new that mame2003 stored those cfg files below the roms dir.

Ok, I think I figured it out. For some reason I had a es_systems.cfg in my ~/.emulationstation that was causing a conflict. I've renamed it, and I'm now able to see my 3 ROMS.

That appears to be the case. I re-flashed the image many times, but a new card did the trick. Funny that card had worked fine before. Thanks!

Is this likely to be something someone in the Retroarch forums could help with BuZz or do you not think it would work anyway ?

@xl97 second controller should just work. does it work for 2 player in other lr- emulators (like SNES, etc)?

@synack, The Pi works fine when I put my Raspbian card in and boot it up, so I think the Pi is fine.

@jamesP 2A should be ok for a Pi2, especially if it came with it! But if you have 2.5A supply to try then the more spare capacity the better.