
Originally Posted by https://steamcommunity.com/discussions/forum/1/358415206084594716/
Steam games normally can't be added to exceptions list of DEP. When you try to add them, you will get an error saying "This program must run with data execution protection", and so you must turn off DEP altogether, which I think isn't a good thing to do for your computer's sake, otherwise you won't be able to run the game. This is the case with most of the older games.
So here's how you add steam games to that exceptions list:
- Run regedit.exe
- Go to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\Current Version\AppCompatFlags\Layers
- Right-click Layers directory and create a new string value.
- Make that string value's name path to your game's exe,
e.g. E:\Program Files (x86)\Steam\steamapps\common\GameName\Game.exe
- After creating string value, right click to it and select modify then copy and paste DisableNXShowUI to "value data"
- Go to DEP and check your exception list, game's exe should be there now. If not try again.
- Restart computer.