Hi,

Was hoping some wonderful person could assist. For whatever reason a good proportion of older GOG games (examples: Alien Breed, Sensible World of Soccer....), all appear as small window at center of a black bordered full screen display. It IS full screen as I am able to At-Tab out of it to a window. I currently run my desktop display at 3840x2160 with scaling set to 200% I am conciously aware that this can affect some games so I have gone into what I think is the .exe for the games and disabled scaling for these games and also set run in 640x480 but this does not seem to fix the issue. I wonder if I am applying the compatibility settings to the right exe or if Im barking up the wrong tree altogether. Any advice?

Why would you disable scaling? That's the exact opposite of what you want here.
The problem is in your DOSBox config file for the game. It has nothing to do with the game's exe file. You are indeed barking up the wrong tree.

Sounds like a problem that has been asked before. Maybe the answer that worked here will help?

https://www.gog.com/forum/general/cant_play_dosbox_games_in_normal_fullscreen_anymore/page1

EDIT: Oh, hah. paladin was the one who solved it there, too ;)

As Paladin181 said, re-enable DOSBox scaling. The issue is, Windows scaling settings may affect the DOSBox window itself, but it doesn't affect DOS games emulated *inside* DOSBox. You still need DOSBox to do the scaling for DOS games, even if the DOSBox window itself is fullscreen.

First thing, go into the DOSbox config file in the game's directory and change the resolution and output mode.

Something like

output=ddraw

or

output=opengl

or

output=openglnb

The problem is that the default that GOG uses (for mass compatibility with as many machines as possible) doesn't automatically scale to full screen. Try the above 3 out and see which runs and looks the best. If you see no difference then it doesn't matter which you use.

Next, change the resolution:

fullresolution=0x0

0x0 automatically makes it use the video mode you're already in, i.e. your desktop resolution.

Changing the output mode to one of those and the resolution to 0x0 should fix the main problem. Some other people have suggested changing the scaler mode. This is a good thing to do, but I don't think that it (by itself) would fix your problem. Personally I like scaler=normal3x but there are some fancy upscaling modes listed in there that I don't care for but you might.
Lastly, set aspect=true, which makes non-square pixel modes like 320x200 display correctly. Generally speaking you can just turn this on for every game, but very very occasionally you might get a game where this correction makes everything look too tall, in that case just turn it off for that game.

I notice with a rather more useful reply than the one his provided this time!

Any luck? Paladin's and my solutions both solve the same problem in very different ways but really you should do both. Paladin's should help for other games as well and is a good thing to do in general and mine should stop the dosbox games being a blurry mess.

Paladins fix was the key. Thanks for the response.

As I said, both work but I really do recommend doing mine as well. Simple interpolated scaling from 320x240 up to 3840x2160 will almost certainly introduce a ridiculous amount of blur. Paladin's fix was to make low resolution things to scale up to full screen, mine was to get DOSBox running at your resolution.