What is the most immediate and common solution for the 'game requires a system restart' error in Valorant?

The most immediate and often effective solution is a genuine system restart. This means going to the Start Menu, selecting Power, and choosing 'Restart' rather than just shutting down and powering back on. A full restart ensures that all system processes, including those related to Riot Vanguard (Valorant's anti-cheat), are completely refreshed and reinitialized, which can resolve temporary conflicts or corrupt states that trigger the error.