Outdated or incorrect graphics drivers are a common cause of configuration mismatch errors. Make sure your graphics card drivers are up to date. You can check for updates on the official website of your graphics card manufacturer (NVIDIA, AMD, or Intel).
Overlays from programs like Discord, Steam, or NVIDIA can sometimes interfere with games. Try disabling them:
Close any unnecessary programs running in the background.
This error is extremely common on gaming laptops with switchable graphics (e.g., NVIDIA Optimus or AMD Switchable Graphics). The game detects your Intel integrated GPU at launch, then tries to switch to your NVIDIA/AMD GPU during gameplay. Outdated or incorrect graphics drivers are a common
For NVIDIA users:
For AMD users:
Once forced, the game will see the same GPU from boot to menu, eliminating the mismatch. Close any unnecessary programs running in the background
Navigate to:
%userprofile%\Documents\SEGA\Sonic Generations\
(or Documents/SEGA/Sonic Generations/ on Steam Deck/Linux)
Delete Configuration.config – not the save files, just that one. For AMD users:
Now launch the game. It will recreate the config and re-detect your hardware.
Before editing any files, try this counter-intuitive method:
Sometimes, the game just needs to overwrite the old config file with a fresh hardware scan. If this works, the error will not reappear until your hardware changes again.
The most common advice on forums is to set your Configuration.config file to “Read-Only” after applying your desired settings. While this prevents the game from resetting the values, it introduces a secondary problem: The error message still appears every time you launch the game.
Even with Read-Only enabled, the game detects the mismatch, throws the error box, tries (and fails) to write new defaults, and then loads the Read-Only settings. You still have to click “OK” through the popup every single time. For many, this is unacceptable.