ginjirou wrote: ↑Wed Jul 11, 2018 4:06 am
I am using the official build from the site which I updated two weeks ago. A front end is the only way I know how to run MAME. I will try playing with the horizontal stretch sliders and get back to you whether that resolves the issue. This issue shows up both in windowed and full screen modes, but is more pronounced in windowed mode. This does not happen with the other unofficial MAME builds that I have such as MAMEUI64
There is nothing default to MAME's setup that would cause your output to show like you have presented.
MAME has an internal front-end which is capable enough to run any title it can find a romset for. I would suggest installing the latest (0.199) in a new folder and then either drag a romset you want to test to "ROMS" in that new folder or launch MAME64 and set your rompath in the user interface: Configure options -> Configure Directories -> ROMs .. adding whatever folders needed.
My guess is that, by default, things should work fine for you. Since you give no driver/video card information we are left to guess just what is happening on your system other than you seem to be using Windwos 10 unactivated.