Check and select Windows 7 or Windows 8 . 5. Disable Antivirus and Overlays
DmC: Devil May Cry uses an older version of Steam’s DRM wrapper. When you press "Play," Steam tells the game, "Hey, it’s cool, let them play." However, due to modern operating system security, compatibility layers (Proton/WINE), or corrupted local files, the game’s executable loses track of the parent Steam process. The game looks for steam.exe or steamwebhelper.exe , doesn't see it, and throws the error. Check and select Windows 7 or Windows 8
Here are the top fixes, ranked from the easiest to the most advanced. " Steam tells the game