@Floob @dankcushions Thank you. I just had som eoveride of menu_driver in the retroarch.cfg from some systems folder so i still had rgui for some emulations. but know i have matched everything against the parent retroarch.cfg menu_driver and it works.

Without seeing a log file - /dev/shm/runcommand.log - or the actual configuration file, it's difficult to say what is wrong. The default configuration file installed by RetroPie should always work (retroarch.cfg.rp-dist).

Also, please add the info requested in https://retropie.org.uk/forum/topic/3/read-this-first.

Just follow rsn8887 advice, but keep in mind that if you changed Retroarch option save on exit the core will revert to rgui despite main configuration, you have to edit cfg file on system folder.

About the rgui default
I think the big thing is the compatibility, xmb is not so snappy with shader activated and 1080p on Pi3, it decrease to 30 fps immediately and is slightly laggy. Nothing to worry too much, but is noticeable.
Also the 4:3 format i suppose, xmb is not so good and even i prefer rgui since i like bezels, but the rsn887 point about additional info cannot be overlooked, is more complete for sure, seems xmb is the new gold standard of Retroarch dev.

Twinaphex said the he would like to fix this color shifting bug but somehow the bug hasn't been fully documented yet. Probably not on the fast track to a fix :(

@mediamogul It works great for me too, I changed a long time ago. RGUI just offended my eyes. The only thing I had to do was add an icon for netplay that was missing on the retroactive icon theme I use. I couldn't bear to look at a black square where it should have been. I think personally that RGUI is used to keep the technophobes and noobs away from using it!