Still getting Code 12 on 1903 V1 18362.30  

Update!

I managed to get my system working again.

Below is a list of the exact steps I take whenever I need to reset bootcamp. This time around though, I would use DDU and it seemed to work - until i began downloading the Radeon driver. When looking at my Device Manager, it would list the standard "Windows Driver" but once i began the Radeon download it would somehow switch back to Intel (very frustrating). Anyway, i continued to get the Error 207 message at the end of the Radeon Download- This states that the download was completed but windows found an issue (Code 12). I ended up following through as if the download had completed. I restarted once, unplug my gpu, re-plug on login and repeat. After the download completed I restarted my system twice, now its working easy as pie...

Detailed steps below for reference:

1. Install Windows 10 Pro as normal using the Boot Camp Utility. I used Win10 v2008
2. Let the Boot Camp Assistant install the standard drivers.
3. Reboot into safe mode and run  DDU . I asked it to wipe  AMD drivers . I don’t know if this step is required, however the guide this was based off did so I did it. Note that Bluetooth may not work in Safe Mode, so plug your keyboard in via USB for this step.
4. Reboot back into Windows as normal, and let all the Windows Update run. Several reboots will be required, so be ready to hustle that along. Whilst it’s downloading, go grab the latest  AMD drivers  but don’t install them yet. I used the Radeon Adrenalin 2020 20.9.1 from 16th Sept.
5. After the updates are completed, plug in / turn on your eGPU. It won’t work, but it’ll allow the  AMD drivers  to install. Painfully, if the eGPU isn’t connected, the driver app will quit as it starts with no prompt… annoying. I selected Factory Reset to “Yes”.
6. When the first stage of the  AMD drivers  has finished and it’s ready to reset, press restart and unplug the eGPU.
7. When the system is back at the login screen, plug your eGPU back in. This is important, as the  AMD driver  setup will continue when you log in, and if it can’t find the card, it’ll quit and you’ll need to start back at step 5.
8. When the installation is finished, click restart and again unplug the eGPU.
9. When the system starts back up, log in and turn on the eGPU. It’ll fail to start in the device manager however this is expected. Restart again, however as you’re restarting unplug the HDMI cable from the monitor that was directly connected.
10. When Windows 10 boots, you should be looking at your login screen through the eGPU. Huzzah!

Credit to @jazzdogg for the instructions. This is the exact process i've used many times before but jazzdogg went above and beyond to provide detailed instructions.

Thanks!

@fiesta5ever, most welcome. Glad you got it working. By chance, are you having issues when you right click on the desktop and click "Display settings"? Does the settings app appear and then crash again shortly thereafter?

@jazzdogg, I'm not having any issue accessing display settings from right click on the desktop. I'm able to right click and change my resolution no problem. I get an easy 50FPS in most AAA games at 1440p.

I assume you ask because you're having this issue? Are you able to access via settings from the windows start menu at bottom left?

@fiesta5ever, I can access settings from the start menu, however there's no display section. Which drivers did you install?

@jazzdogg, Im using Radeon 20.4.2. Have you resolved this issue or still using the work around?

On another note, I just noticed a post regarding new Error 12 solution - Hackflags 0X600 Reg Edit. Might give this a try.

@fiesta5ever, I’m still having the issue with no workaround available, I just turn off the monitor haha. 

I haven’t heard about the regedit, I’ll have to take a gander.