The message became a mantra. Steam must be running. He was running. The computer was running. The fan was whirring like a chainsaw. But the digital gatekeeper refused to budge.
How to Fix "Steam Must Be Running to Play This Game" in Resident Evil 4
In 95% of cases, or Solution 2 (Kill background Steam processes) will get Leon Kennedy back on his feet. For the remaining 5%, working through file verification, antivirus exclusions, and repairing the Steam service will banish the error for good. The message became a mantra
When both Steam and the game run under the same elevated token, Steam’s API handshake succeeds.
Your antivirus or Windows Defender may be overzealous. It might quarantine a key game file or block the executable from loading, leading to the "Steam must be running" error because the game can't make its required handshake with Steam. The computer was running
Unstable Steam Beta client updates can break compatibility with specific game titles. Switching back to the stable public version of Steam often solves initialization errors.
If nothing else works, the Steam installation itself is likely broken. Do not uninstall your games; you only need to reinstall the client. How to Fix "Steam Must Be Running to
Reinstall the game (preserve save if needed)