In Steam, go to > Downloads and click Clear Download Cache .
The error "Steam must be running to play this game" in DmC: Devil May Cry In Steam, go to > Downloads and click Clear Download Cache
Click to repair any corrupted data.
Does this resolve the error for you, or would you like help ? In Steam, go to > Downloads and click Clear Download Cache
Completely close Steam (check the system tray to ensure it's fully closed). In Steam, go to > Downloads and click Clear Download Cache
Are you running the of the game, or are you utilizing a custom setup or mod?