What exactly 'not working' means ? EmulationStation doesn't start ? Games aren't working ? Installation is not completing ?
Please add more details about your setup, including the Ubuntu version and hardware details.

mmmmmm... slowly i begin to understand better how all works :)

@quicksilver They are! more so than i thought they'd be. It's not ready for prime time to the extent that all the titles seem to have slowdowns or small rendering issues, but so far Scud Race, Sega Rally 2, Virtua Fighter 3 and Spikeout have all been immensely playable.

@jimiretro Usually you get a message only on errors.
If the mount command worked, then check if the roms folder is populated, then start EmulatonStation.

@oathbetrayer The Docs have a section for getting started. You don't need NOOBS for RetroPie, you can just flash/install the latest image and it will be enough to get you started.

You've probably modified one of the start-up services which you shouldn't have. Post the contents of /etc/profile.d/10-retropie.sh file from your system.

@jorgejohnson72 please fill out https://retropie.org.uk/forum/topic/3/read-this-first

and be sure to include the full path, file name and extension of the rom you’re not seeing

Got it. Had to open the web developer in Firefox and it just worked.
No clue as to why, but I got my homepage set to categories so I don't get an error and I can logout.

@grimdanfango Yes, Hotkey + Quit should exit RetroArch.

All the info you need to know here ...

https://retropie.org.uk/docs/Themes/

or, if you want to manually download a theme via your PC and install it in Retropie/Emulationstation

download it, unzip it and copy it here ...

/etc/emulationstation/themes

then, restart Emulationstation and following the guide above, you will be able to select and apply it

@dankcushions good advice. Thanks.

Ok, it worked, thanks for the advice!

@retro81 Actually I may make it ask the user to update from RetroPie-Setup, to keep updating handled in one place.

@leon21
You can find old versions of Retropie here - https://github.com/RetroPie/RetroPie-Setup/releases

To be honest, I would try a different version of the rom and see if that works rather than downgrading Retropie.

@iandaemon I think that won't work if the ROM names have non-latin characters, the 'Jump to ' will not show those.
@jan_L what version of EmulationStation are you using ?

@xallius 3rd party images aren't supported on the forums, especially ones that come pre-loaded with game ROMS.

I'd suggest going back to the seller for support, or install the official image from the Retropie site and then the community will be able to assist you.

@xionyus as I’ve told countless others that are new here with prebuilt systems, retropie is not a product you buy, but a hobbyist project that lets people build their own retro console. There is no firmware, there is no single programmer. It’s a mishmash of many different programs and projects by many different people. The retropie developers just brought them all together into a nice tidy little package. But it far from a full retail package.
The reason why we can’t help you is a lot of us know how retropie is supposed to work out of the box, with the base image. And is pretty simple. If something goes wrong, it requires your knowledge of what you did to figure out what’s going on. We have no idea what a 3rd party did, therefore can’t help.
Try starting over and enjoy the journey of how all the pieces work together, like how many of us started.