@dieuy Have you tested it on another TV?
Have you tested with another HDMI cable?

@spyhunter10 Do a clean install of the latest version of Recalbox and try again:
https://archive.recalbox.com/

Did redoing the installation solve the problem? If not, what hardware are you using? Are you using the correct BIOS? Is ROMSET correct? Have you tried changing the emulator / emulation core?

To avoid problems with Arcade games, read:
https://github.com/recalbox/recalbox-os/wiki/Easy-Arcade-on-Recalbox-(EN)
https://github.com/recalbox/recalbox-os/wiki/Advanced-Arcade-on-Recalbox-(EN)
https://github.com/recalbox/recalbox-os/wiki/Check-your-roms-version-with-clrmamepro-(EN)
https://github.com/recalbox/recalbox-os/wiki/Add-system-bios-(EN)

@Yonder Hi

For God Knows which reason, retroarch defined buttons like :
1 -> B
2 -> Y
3 -> A
4 -> X

Which is totally illogical with their idea of A to validate and B to cancel (thus making it work with any pad).

BUT : you can use the "core remap" feature : buttons will be remapped according to how you set them up. You do it once for all for every 8bit core

For now it's not officially supported.