@pelletalexandre said in Galaga on mame fail to launch:

It was just about setting mame 2003 instead of mame 2003 plus...

It seems there are a lot of things that got fixed in galaga after mame2003/0.78, that's why mame2003-plus uses a more recent version of the driver, which needs a more recent version of the romset (probably mame2010/0.139). From what i'm seeing in the mame changelog, i wouldn't recommend using mame2003/0.78 to play galaga.