Vanguard received an additional hotfix over the last hour with a fix for players that experience Error 44 – Vanguard not initialized. It seems to fix it for some players, but not all. We still have quite a bit of players in our Discord that, even after the hotfix was installed and they rebooted, still not can play VALORANT and get greeted by the error.
For everybody who also still experiences the problem, please try the steps from the linked guide above. You might also want to check your Riot Vanguard folder if todays hotfix really got applied – by checking if some of the files like the vgc.exe have May 8th as date.
Anti-cheat lead arkem (Paul Chamberlain) announced this second hotfix earlier. He also mentions that they do not plan to spam updates like this in the future and are also working on the error messaging.