[Getting Arcade to work from within Launchbox (MAME)]

I have installed the stable 6.2 version and is now (re)populating the Launchbox. So far I just added the Arcade part and watched the excellent video on youtube. https://youtu.be/SUQzvbweVgw?list=PL6pTDaHeAz-WMcNURVPU-1xLN_TVpT3FB Im trying to get the games loaded but the mamewindow just pops up and disappears. What am I doing wrong? Windows 10 / Launchbox 6.2 premium / 0.174 roms and 0.174 version of mame64.exe