tl;dr
If you’re stuck in a BSOD loop, can’t use your keyboard to enter safe mode, and have Valorant and/or Corsair Unity Engine installed with either vgk.sys or CorsairVBusDriver.sys highlighted as what failed, then use Command Prompt to find and delete both of them. They conflict with the most recent Windows December 2020 update.
Valorant Vanguard and Corsair Drivers cause the BSOD loop
Here’s some context to see if your story closely matches mine. My computer was working fine up until the most recent Windows December 2020 update and then the next morning when I went to power it on (Friday 18 December) I had an immediate BSOD and got stuck in a loop with the stop code “SYSTEM THREAD EXCEPTION NOT HANDLED” specifically highlighting what failed as vgk.sys which is Riot Games’ Valorant Vanguard anti-cheat.
Now, the issue I was having also meant I couldn’t use my keyboard to boot my PC into safe mode and delete the files the usual way, so I had to wait until the BSOD diagnostic tool ran, failed, and then gave me the option to go into Advanced Options > Troubleshoot > Command Prompt.
From there, I found and deleted vgk.sys and restarted but I was still having the same issue.
I then found out from an article on Bleeping Computer that the Windows 10 December 2020 update wasn’t playing nicely with some of Corsair’s drivers – specifically CorsairVBusDriver.sys. Now, I haven’t used a Corsair product on my desktop for some time, but I did have the Corsair Utility Engine installed and it seems that this CorsairVBusDriver.sys driver is what causes the BSOD loop.
How do I use Command Prompt?
In Command Prompt, find your system32/drivers folder by either typing in C: or D: or E: (you get the gist) and using the cd locationname (e.g. cd windows, cd system32, cd drivers) command to enter that folder and use commands like dir to bring up all of the active drivers and check for vkg.sys and CorsairVBusDriver.sys and del /s CorsairVBusDriver.sys to delete the file. My computer had the driver installed across a few different locations (D, G, and the Windows partition on my C drive [ which was X for me]) so I had to hunt down and delete them all but it worked and now I’m back. Once you regain access to your desktop and are out of the BSOD loop, I recommend uninstalling/deleting Corsair Unity Engine off your device until an update/patch fixes the problem.
Hope this helps as I was pulling my hair out for days trying to figure this out!