Updated Oct 2024.
Reinstall Xbox Game bar to generate game's registry key in
HKEY_CURRENT_USER\System\GameConfigStore\Children\
Missing "Flags" registry
You probably also, like I did, encountered a problem where an important registry key needed for tweaking the game's fullscreen behavior was missing from the Registry Editor.
This specific registry key stores information about the game, such as the installation path. It is created when you launch a game however if Xbox Game Bar is not installed, the registry key does not get generated.
Disabling fullscreen optimization (FSO) from the game's .exe won't actually give true fullscreen. Windows volume slider overlay will still appear on top of the game when adjusting windows volume.
You can check this reddit post to understand what registry key I am talking about.
How to reinstall Windows Store and Xbox Game Bar
Open Command Prompt or Windows Terminal as admin and run this code:
wsreset -i
Or try this link below for Windows 10 LTSC:
https://github.com/megakarlach/LTSC-Add-MicrosoftStore-2021
It may take a while for it to install. When done, search for and install Xbox app.
Open Xbox app and navigate to (click Sign in to see settings):
- settings → general → dependencies. Install Xbox Gamebar from here.
- sometimes, it's settings → App → dependencies
Once installed, enable Gamebar by navigating to Windows Settings, Gaming, then Gamebar. Its location is the same path as Windows Game Mode.
Launch the game
Now the last step is to run the game. This is to generate the missing registry key mentioned earlier. Refer to the reddit post that I mentioned earlier if the registry key has now appeared. If it is present, you can follow the reddit post for disabling FSO for true fullscreen.
You can disable all Xbox services and Gamebar after.