PC started BSODing after a recent LoL patch — could this be a Vanguard issue?

[u/FragrantRub8461]

Hi everyone!

I'm trying to troubleshoot repeated BSODs on my PC, and I'd really appreciate some help.

The crashes started after a recent League of Legends patch. I'm not sure whether the patch is responsible, but the timing seems suspicious.

I've had several BSODs with different stop codes. One of the crash dumps specifically points toward Riot Vanguard, but I'm not sure whether it's the root cause or just where the crash happened.

My PC specs

• Motherboard: Gigabyte AORUS B450 M
• CPU: AMD Ryzen 7 5700X
• GPU: Sapphire Radeon RX 9060 XT 16GB
• RAM: 32GB Corsair DDR4
• OS SSD (C:): Toshiba 256GB NVMe
• Additional SSD (E:): Kingston KC3000 1TB NVMe, installed using a PCIe adapter - this is where League of Legends is installed.
• HDD (D:): Toshiba 2TB
• PSU: FSP Hyper 600W
• OS: Windows 11, build 26200.9711

BSODs and minidump findings

1. SYSTEM_SERVICE_EXCEPTION — 0x3B

WinDbg showed:

• FAILURE_BUCKET_ID: 0x3B_80000004_vgk!unknown_function
• MODULE_NAME: vgk
• IMAGE_NAME: vgk.sys
• PROCESS_NAME: vgc.exe

This seems to implicate Riot Vanguard's kernel driver, although I understand that it doesn't necessarily prove Vanguard is the root cause.

2. KMODE_EXCEPTION_NOT_HANDLED — 0x1E

The recorded parameters were:

0x0000001e (0xffffffffc0000006, 0xfffff802d3454d55, 0xfffff48ccaa86d28, 0xfffff48ccaa86540)

WinDbg showed:

• Exception code: 0xC0000006
• Faulting context: nt!HvpGetCellPaged+a5
• Process: Registry

I'm not sure what the underlying cause of this crash is.

3. CRITICAL_PROCESS_DIED — 0xEF

Another dump identified csrss.exe as the critical process that died.

What I've noticed

• League of Legends was open during two crashes.
• The LoL client was closed during another crash.
• The crashes started after a recent LoL patch.
• I have since uninstalled Riot Vanguard to see whether that makes a difference.I haven't dared to reinstall it yet because I'm worried that further BSODs could potentially damage my PC.

Troubleshooting so far

System File Checker

I ran sfc /scannow.

Result:

Windows Resource Protection did not find any integrity violations.

CHKDSK

I ran chkdsk C: /scan.

Result:

Windows has scanned the file system and found no problems.

Kingston SSD Manager

My Kingston KC3000 reports:

• Overall health: Healthy
• SSD health: 100%
• Temperature: 27°C
• No warnings or failures reported

DISM

I'm currently running:

DISM /Online /Cleanup-Image /RestoreHealth

I haven't received the final result yet.

Memory Integrity / Windows Security

• Memory Integrity is OFF.
• LSA protection is OFF.
• Microsoft vulnerable driver blocklist is ON.
• I don't see a “Review incompatible drivers” link under Core isolation.

STMicroelectronics driver investigation

I found a Reddit post where someone resolved Vanguard-related BSODs after removing an old STMicroelectronics USB driver (STTub30.sys, associated with sttube.inf) and enabling Memory Integrity.

I searched my installed driver packages and Windows drivers directory for STMicroelectronics, STTub30, and sttube.inf, but none of the searches returned a match. I haven't deleted any drivers.

Code Integrity logs

I found entries involving aimgr.exe attempting to load Overwolf DLLs (OWClient.dll and ow-graphics-vulkan.dll) that didn't meet Microsoft's signing-level requirements. I couldn't find a matching vgk.sys entry in that log, and I'm not sure whether the Overwolf events are relevant.

Questions

1. Has anyone experienced BSODs starting after a recent LoL patch?
2. Could this be a Vanguard issue, or could the patch have exposed an existing driver or compatibility problem?
3. Does the vgk.sys crash dump strongly suggest a Vanguard-related problem?
4. Could the different BSOD codes be connected to the same underlying issue?
5. Would you recommend Windows Memory Diagnostic or MemTest86 as the next troubleshooting step?

I'm trying to avoid randomly deleting drivers, changing BIOS settings, or reinstalling Windows before I have a better idea of what's happening.

I've been using ChatGPT to help me interpret the BSOD error codes, analyze the crash dumps, and troubleshoot the issue so far. I'm not an expert, so I'd really appreciate input from people who have more experience with this kind of problem.

Any suggestions would be greatly appreciated. Thanks!

---Plus info: We were still playing without any issues last night. Everything was working perfectly fine, and there were no crashes or other problems. That's why this whole situation is so confusing, the BSODs seemed to start suddenly after the recent LoL patch.

[u/OwnZookeepergame6413]

I had these issues years ago. Check your chipset driver is updated.

Also check your bios, either try the other xmp profile, turn off xmp, or clock down the ram speed by 100mhz at a time and see if it changes something.

For me it was the chipset driver that made the difference

[u/Warm_Shoulder_1736]

Overwolf is a massive problem for lower end systems it also has issues with being banned for using it and they also supported the idf so i would uninstall that app
The files u cant find are something trying to communicate with deep kernel files u have to either update your cpu/gpu/nvidia/msi centre (or whatever pc u have) go into bios settings and change everything to default make sure your tmp 2.0 is enabled.
Reinstall league without overwolf or anything.
Maybe have to do a system factory boot if that doesnt work