Problem resolved. It was the SD card. Even though I've used the same SD card on v3.3 it won't clone v4.0. Bought a Sandisk Ultra and it clones just fine. Weird but glad I figured it out, it was driving me crazy.

I have two Macs, an older iMac and Retina MacBook. When I copy my sd card on the mbpr it copies but the card says its unreadable when I plug it back in. On the older iMac it copies then shows up when I plug it back into the computer. Neither copy actually works on the Pi though. Both give me the screen saying "Error: Resizing existing FAT partition". I'm using Apple Pi Baker on Mac. Any ideas?

As a note, I've gotten this to work on an older version of recalbox on an older computer maybe a year ago but this time around no luck. I can also make a copy of my LibreELEC and it works perfectly fine. I've also tried using Windows via VMWare (using many different programs) which does the exact same thing.

How can I try this out?

I wanted to change my video screen ratio so it isn't cut off at the top and bottom

Would love to see this option added

OK, I got a couple roms working now. I think I had the wrong kind roms (rookie mistake I know). Another issue though; When I change my setting in the emulator (FBA Libretro) to different video settings and save them they don't load the next time. I have to go back into the settings and load the cfg file again. How can I just get it to load the first time?

Thats where I have the rooms. SF3 actually works fine its just any other roms don't work.

I cannot get any roms working in either FBA other than SF3. I have a neogeo bios in the folder and bios folder. Are all the rooms in the readme.txt compatible with this version of Recalbox or is that a general compatibility of FBA? I have gotten maybe 2 out of 30 roms I've tried to work.