vgk.sys BSOD: Fix Riot Vanguard Crashes Safely

A vgk.sys BSOD normally means Windows crashed while Riot Vanguard’s kernel driver was active. It does not, by itself, mean that vgk.sys is malware. Treat it as a driver or system-stability problem first: record the stop code, verify the driver’s location and signature, update Riot and Windows, then test Vanguard separately from the rest of the PC.

On some Intel 13th- and 14th-generation desktop processors, repeated vgk.sys crashes can expose a wider CPU or BIOS stability problem. On other systems, the cause may be a damaged Vanguard installation, an incompatible low-level driver, or a conflict that only occurs when a Riot game starts. The order of the checks matters because deleting the driver file or copying random voltage settings from a forum can make recovery harder.

What is vgk.sys?

vgk.sys is the kernel-mode driver used by Riot Vanguard, the anti-cheat component installed with games such as VALORANT and League of Legends. A legitimate copy is installed and updated by Riot, and Windows should report a valid Riot Games digital signature.

Vanguard historically loaded its driver when Windows started. Riot now also offers an optional On-Demand mode on eligible Windows 11 25H2 systems that pass Vanguard Pre-Check; in that mode, the driver starts with a Riot game and stops afterward.^[1] Therefore, seeing vgk.sys loaded at startup can still be normal on a system that does not use On-Demand mode.

Before changing anything, record these details

• The exact stop code: common reports include SYSTEM_THREAD_EXCEPTION_NOT_HANDLED and KMODE_EXCEPTION_NOT_HANDLED.
• When the crash happens: at Windows startup, when the Riot Client opens, when a match starts, or during unrelated heavy workloads.
• The dump file: keep the newest file from C:\Windows\Minidump if Windows created one. Riot Support may ask for logs or dumps.
• Your CPU and motherboard: note the exact processor model, motherboard or laptop model, and current BIOS version.
• What changed: a Vanguard update, Windows update, BIOS update, new peripheral driver, overclock, undervolt, or new game/anti-cheat install.

If the PC is stuck in a restart loop, use Windows Recovery Environment to reach Safe Mode or uninstall Riot Vanguard from recovery. Do not manually delete vgk.sys from the driver folder as a first step.

Is vgk.sys safe or malware?

Use the service configuration and digital signature instead of trusting the filename alone. Open PowerShell as administrator and run:

Get-CimInstance Win32_SystemDriver -Filter "Name='vgk'" | Select-Object Name, State, StartMode, PathName

Then open the reported file location, right-click vgk.sys, choose Properties, and inspect the Digital Signatures tab. A normal copy should point to the Riot Vanguard installation and have a valid Riot Games signature. The exact folder can change with an update, so the service’s PathName is more useful than a path copied from somebody else’s PC.

For a suspicious wrong-path copy, follow the broader file-safety verification checklist and submit the exact file to the Gridinsoft Online Virus Scanner. Do not upload private crash dumps: they can contain usernames, paths, and fragments of memory.

How to fix a vgk.sys BSOD safely

1. Return the system to supported settings. Disable experimental CPU or memory tuning for the test. If you changed BIOS settings recently, use the motherboard vendor’s documented defaults rather than guessing individual voltages.
2. Install pending Windows and Riot updates. Restart Windows after both are current. Also install stable chipset, storage, and graphics drivers from the PC or component manufacturer.
3. Repair or reinstall Vanguard. In Settings → Apps → Installed apps, uninstall Riot Vanguard, restart the PC, open the Riot Client to reinstall Vanguard, and restart again when prompted. Riot’s own support flow uses a clean reinstall and escalation when the problem remains.^[2]
4. Test without Vanguard. If the BSOD disappears only while Vanguard is uninstalled, the interaction is isolated to Vanguard or another low-level component it meets. Collect Riot Repair Tool logs and open a Riot Support ticket instead of deleting driver files.
5. Test the rest of the PC. If crashes also happen in other games, compression tests, shader compilation, or normal desktop use, investigate the broader system. See the Windows freeze checklist and the guide for a PC that restarts randomly.

Intel 13th/14th Gen: check BIOS stability before blaming Vanguard

This branch is especially important for desktop Core 13th- or 14th-generation systems, including many K, KF, and KS models. Intel documented a voltage-related instability issue that can cause repeated application crashes, operating-system crashes, hangs, and errors. Intel’s guidance is to install the latest BIOS from the motherboard or system manufacturer and use the supported Intel Default Settings.^[3]

1. Identify the exact motherboard or prebuilt-PC model.
2. Read that manufacturer’s BIOS instructions and release notes.
3. Install the latest stable BIOS that includes the relevant Intel microcode updates.
4. Load the vendor’s Intel Default Settings or equivalent supported baseline.
5. Retest Vanguard and at least one unrelated workload.

Do not copy a stranger’s manual voltage, multiplier, or load-line calibration values. Two systems with the same CPU can have different boards, firmware, cooling, and silicon condition. If the PC still crashes across unrelated applications after a supported BIOS update and default settings, contact the system maker or Intel about hardware support.

If Vanguard still crashes on AMD or a stable Intel system

A kernel anti-cheat driver can meet storage, RGB, monitoring, virtualization, overlay, and other anti-cheat drivers in the same privileged part of Windows. That does not prove which component is defective. Use a controlled isolation process:

• perform a Microsoft clean boot while keeping Microsoft services enabled;
• remove obsolete motherboard utilities, hardware monitors, or old anti-cheat components one at a time;
• update storage and chipset drivers from the hardware manufacturer;
• disconnect nonessential USB devices for one test;
• restore Windows Exploit Protection settings to their defaults if they were customized;
• save a fresh dump after each meaningful change so the tests remain comparable.

Change one variable at a time. Bulk driver-updater tools and “one-click BSOD repair” utilities make the result harder to interpret and may install the wrong driver.

When a security scan is warranted

A security scan is not the first fix for a correctly signed Riot driver. It becomes appropriate when vgk.sys is unsigned, loads from an unrelated folder, appeared after a cheat loader or unofficial game repack, or the PC also has blocked outbound traffic, unknown startup entries, browser changes, or repeated security warnings. Removing the visible file alone may leave a loader, service, scheduled task, or exclusion that restores it.

What not to do

• Do not delete vgk.sys by hand while its service is installed.
• Do not disable Secure Boot, TPM, VBS, or driver-signature enforcement just to make the game start.
• Do not apply random undervolt or overclock values from a forum or video.
• Do not assume every dump that names vgk.sys proves Vanguard is the root cause.
• Do not restore or allow an unsigned wrong-path copy because the filename looks familiar.

FAQ

References

1. Riot Games. “Vanguard On-Demand — Anti-Cheat Update.” Riot Games, June 24, 2026; accessed July 20, 2026. Riot Games update.
2. Riot Games Support. “vgk.sys Error Troubleshooting (13th and 14th Generation Intel CPUs).” Riot Games, accessed July 20, 2026. Riot Support guide.
3. Intel Corporation. “Intel Core 13th and 14th Gen Instability: Customer Passthrough Statements.” Intel, August 15, 2024; accessed July 20, 2026. Intel technical statement.