A missing or altered steam_api.dll is the #1 cause of this error.
The "Dmc Devil May Cry Steam must be running to play this" error has been a persistent issue for PC players on Steam, with no clear solution in sight. While troubleshooting steps and community workarounds can help alleviate the problem, it highlights the need for game developers and publishers to prioritize player experience and provide more flexible, user-friendly DRM solutions. Dmc Devil May Cry Steam Must Be Running To Play This
The most common cause is a hung process where Steam appears to be open but isn't responding to the game's verification requests. A missing or altered steam_api