Before attempting the fixes below, ensure you have tried the basics:

It was a custom .ini file named dsound.ini with instructions to place it in System32 (big red flag) and also in the game’s Binaries folder. The contents were cryptic:

To fix the "Steam must be running to play this game" error for , the most effective solution is often deleting specific cache files or adjusting administrative permissions . Primary Fixes

If none of the above solutions work, you may need to:

Run DmC without these running in the background: