The reason this is a controversy now is probably that, A) Valorant is a high-profile new game and Riot intentionally drew a lot of attention to its anti-cheat efforts, B) Vanguard starts with Windows instead of with the game, and C) Vanguard doesn't seem to be as lenient as other anti-cheat software, possibly blocking a wider array of programs. Just like Vanguard, these anti-cheat programs block other kernel drivers that contain security vulnerabilities. BattleEye also does, and it's used by high-profile games such as Rainbow Six Siege and PUBG. EasyAntiCheat does, and it's used by a ton of games, including Apex Legends.

Regarding that last point, it's actually common for anti-cheat software to utilize kernel-mode drivers. Other anti-cheat software also uses kernel-mode drivers.Cheat makers work at the kernel level, and if Riot can't give its software the same level of privilege as the cheats, it'll be at a disadvantage.It has been careful, and has offered a $100,000 bounty for the discovery of security vulnerabilities in its software.The primary argument against letting Riot run a kernel-mode driver on your PC is that if someone found a security vulnerability in it, the consequences could be much worse than if a vulnerability were discovered in regular, user-level software. Software that runs at the kernel level has the greatest level of control over your PC. It's the core of your operating system, where the most basic functions happen, such as allocating system memory to different programs. If we were in a '90s hacker movie, the kernel would be the virtual reality sphere of green code where the final showdown takes place. What does it mean that the Vanguard driver is 'kernel-mode'? That's why you have to reboot after installing Vanguard. If Vanguard's driver isn't started with Windows, Valorant won't trust your PC, and you won't be able to play. It doesn't collect data about your PC or send anything to Riot: It looks at other drivers and blocks them from running if it detects that they have a known vulnerability that could be used to compromise the anti-cheat client. (Vanguard blocks fewer programs as of an update in May, and in the future may prevent Valorant from running instead of blocking the offending software.) The kernel-mode driver is the client's bodyguard, basically. A client that checks to make sure you aren't running any cheats while you're playing Valorant.A kernel-mode driver that runs when your PC boots up.

Riot vanguard install