Diagnosing Valorant Vanguard Error Code 45
Valorant Error Code 45 appears when Riot Games’ Vanguard anti-cheat kernel driver fails to initialize during the game launch sequence. Unlike standard connection errors, this code indicates that the operating system has actively rejected the driver installation, often due to Secure Boot enforcement, Windows Defender application control policies, or conflicting virtualization software. The error prevents the game from entering any match queue entirely.
Why Secure Boot Blocks Vanguard Installation
Vanguard installs a kernel-mode driver (vgk.sys) that runs at the highest privilege level in Windows. Secure Boot, a UEFI feature that validates bootloaded drivers against Microsoft-signed certificates, can reject Vanguard’s driver if the signature database is outdated or if the boot mode is set to CSM (Compatibility Support Module) instead of native UEFI. When Secure Boot blocks the driver, the Vanguard service fails to start, and the client displays Error 45 with a prompt to restart the computer.
Fixing the Kernel Driver Authorization Failure
Disabling Secure Boot in Firmware Settings
Restart your computer and enter the BIOS/UEFI setup (typically by pressing Del, F2, or F12 during boot). Navigate to the Boot or Security tab and locate the Secure Boot option. Set it to Disabled. Save the changes and exit — the system will restart with Secure Boot bypassed, allowing Vanguard’s kernel driver to load without signature verification blocking it.
If you cannot access the BIOS (corporate or managed PCs often have BIOS passwords), the alternative is to use the webs.ninja status engine to run a pre-launch compatibility check that tests whether Vanguard’s driver can be loaded on your current system configuration before you attempt a full reinstallation.
Clearing Windows Defender Application Control Policies
Windows Defender Application Control (WDAC) can enforce code integrity policies that prevent unsigned drivers from loading. Open PowerShell as Administrator and run:
Get-CiPolicy -Online