@mitu I ended up figuring it out (by accident), I had 2 partitions on the SD card. Even though there was only one named root it was confusing the system. I was using the image for pi 0/1 and had imaged the card with Win32DiskImager.
Any chance someone could translate this fix in to layman's for a newbie?
The only applicable advice in the above topic is
uninstall es dev, reinstall regular binary
Try re-installing your EmulationStation package, either from binary or from source.
So,, I tried the advice here from both Binary and source. I even removed all exp packages just to ensure it wasn't anything in there. The error still appears and now i've decided to attempt a complete rebuild from Raspbian up. I am also increasing SD capacity from 16gb to 32 GB to ensure space isn't an issue.
So, I did a basic install and then removed all main packages then proceeded to reinstall the main packages from source. See what happens there
@da_kicks_87 Who knows what could have caused it. If it were me, I would reformat the SD card and then flash the backup image to the card. If you still have issues, you may possibly have a faulty SD card.
@WilsonB Yeah, it's a bad post, makes you look seriously lazy. You need to read the guide. MAME roms are not universal. More importantly though https://retropie.org.uk/forum/topic/3/read-this-first. Angry with my response? don't be. Be angry with yourself. People on this forum spend countless hours repeating the same old thing over and over and over and over and over and over because people do not read the guide. For example, I wrote this. I spent time doing it to prevent this question. It complements the full guide. Have you read it? Have you read this? I say No. No. No. No. No you have not.