ERROR 12 on BOOTCAMP HAS BEEN FIXED BY MICROSOFT! in WINDOWS INSIDER (FAST) !  

Windows 10 on the latest fast ring isn't working for me - build 20211.1000. I'm getting error 12. Previously I had a fully updated Win 10 install w/ BCD August drivers and tried the pci.sys method and Windows wouldn't even boot! I took a chance an upgraded to the Insider build based on people saying it was working - but not for me.

MacBook Pro 16" 5500m

Razer Core X

Powercooler Red Devil 5700 xt

@nudoru, 

Just FYI, there’s a report of the latest regular build (Windows 10 Version 2004, Build 19041.508) working without error 12 here:

https://egpu.io/forums/bootcamp/egpu-working-on-windows-2004-no-workarounds-needed-wth/#post-86319

@mini-i5 that’s the version I have and it’s a no-go on 16 inch+5500m+5700xt egpu due to error 12. 

Maybe try the april bcd drivers?

That's what worked for me.

Argh, I just wish Windows could make their stuff more consistent - that's the one thing I like about Macs, even with apple-enforced limitations--> minimal driver fussing needed.

It either works or it doesn't work --> more time for more productive stuff

Do you have an extra thunderbolt device connected to your computer?

I had resource probs with that a little while back, since my external thunderbolt drive and the eGPU were both connected to one side of my MBP 16" (and thus had to share the same controller).

I tried everything: only egpu connected and switched ports, connected my USB C hub. Nothing worked. And if I connect my nvme enclosure (only the enclosure) windows hangs at login screen and laptop reboots. I'm building a sffpc now, f* it.

@florin_samareanu, That is the same issue I had back in April.  I require the pci.sys hack to get the eGPU to work with my 5700XT (16" MBP with 5500m) in Windows 10 1909.  I upgraded to the GM version of Win10 2004 when it was available in the fast ring, and my system wouldn't even boot after I reapplied the pci.sys file.  The system would Error 12 on me without the pci.sys file.  I just have not wanted to break my setup since then, which is why I haven't played with it again.

I might take a stab once the 20H2 version is released later this year.

Hey all, I just got my sonnet 550.  As an Nvdia user (1650 low profile repurposed from optiplex sff), will I still need the EFI boot if I go the Fast/DEV route?

Edit: strictly using Windows only, gaming mostly

I updated to the latest fast build but I still get the error 12

fast ring upades works from time to time (more often works) - maybe they're just drunk there or something...

@nicholasdc, Ive tried this and doesnt work for me