@benjiman You can use the File Manager - in the RetroPie system menu - to look in the file directly on the Pi, but it's easier if you have a PC and connect via file shares at \\retropie\configs\all\emulators.cfg.
Stick with official plug and play devices like (s)nes classic mini
Start a new hobby creating your own personalized Retropie system by starting from scratch. It's not that hard. All the information is readily available on this website. You may want to invest in a quality micro sd card first.
@saint_jimmy Happy to help! No, just follow the instructions and from then on you can just plug your usb flash drive in your pc and transfer your games to the usb. Save files will be stored there as well.
After much hair pulling and searching, I managed to find the solution to my issue. All of my ROMs except for Gunstar Heroes was a 0kb file. Once I replaced the empty files with good ones, they all played perfectly.
Update on this. I was able to get this to work with previous images, and the ones I made off my disc. I had to wipe my SD card and completely re install Retropie 4.2 from scratch. I am not exactly sure, but maybe something did not update properly when I updated from a previous build.