Valorant Error Code 57, Riot Vanguard not initialized
Error code 57, listed by Riot as PlayerAffinityInitFailure, means Riot Vanguard, the anti-cheat service Valorant needs, did not start properly. The game cannot run without Vanguard, so the fix is to get Vanguard running again, starting with a restart of the client and the PC.
The fix, in order
Restart the Riot Client. Close Valorant and the Riot Client fully, then launch Valorant from the Riot Client again, which restarts Vanguard with it.
Restart the PC. Vanguard is a system service that starts with Windows, and a restart is the most reliable way to get it running again after a failed start.
Check that Vanguard is running. Press Ctrl plus Shift plus Esc to open Task Manager, look for the Vanguard tray icon or the vgc service, and if it is missing, restart the PC again.
Run the Riot Client as administrator. Right-click the Riot Client and choose Run as administrator, which lets it start Vanguard without a permissions block.
Reinstall Riot Vanguard. Uninstall Vanguard from Windows Settings, then launch Valorant, which will reinstall Vanguard automatically, and restart the PC when asked.
Check for a Windows update. An outdated Windows install can stop Vanguard from starting, so install pending updates and restart.
Do not disable Vanguard to avoid this error. Valorant will not run without Vanguard, and tampering with it can trigger anti-cheat action on the account. If Vanguard will not start, reinstalling it is the safe fix.
If it still happens
If error 57 keeps appearing after a Vanguard reinstall, check that no other anti-cheat or security software is conflicting with it, and make sure Windows is fully updated. If it still fails, contact Riot Support, since a Vanguard startup failure that survives a reinstall can need a look at the system itself.
Common questions
What is Riot Vanguard? Vanguard is Riot's anti-cheat software, and it runs as a system service whenever Valorant is played. Valorant refuses to start if Vanguard is not running, which is what error 57 reports.
Is error code 57 a ban? No. It means Vanguard failed to start, not that the account is banned. It is a startup problem on the PC.
Why does error 57 appear after a Windows update? Windows updates can interrupt Vanguard's service or change its startup state. A restart normally restores it, and reinstalling Vanguard fixes it if the restart does not.