This is happening in GameEx and Acade Edition.
Occasionally when starting a game, it will just be black, but the sound works. Usually we can exit and restart, then it works okay. But sometimes once it goes black, we can never get a display back, and have to either use Alt+F4 to quit hard, which doesn't always work either.
In the attached log, the first time I tried to run 1945kiii it did this. The log indicates that after I exited MAME (which I could not see), there is an message about "Display is running in full screen compatibility mode." I am not really sure what this means, but the second time I tried to run it, it worked fine, and that message did not appear after exiting MAME.
I have already tried forcing windowed full screen (GameEx), removing HideOS, etc, and none of that made a difference.
The PC is dedicated for a cab. It's got a fresh OS install and nothing but the system/video drivers installed, along with MAME and GameEx. When I first noticed this happening, I had not yet installed the AMD drivers for the integrated Radeon video in the 3400G. So I installed the AMD drivers, but nothing changed.
Again, this affects GameEx and GameEx Arcade Edition. I really love Arcade Edition and want this to work. If I could at least always exit MAME when it doesn't show video and try again, that would at least be workable for my family, but sometimes we can't get that to work either, and the kids yell "Daaaaaad" and I have to pull the keyboard out and.... well. :-)
log.txt
GameEx.ini