Like many of us, I'm planning an upgrade to the base image used across the site. Whilst I know that Windows 10 2004 is having a slightly shaky start to life, I'm going with the latest version, and hoping that any issues are patched.

So, I downloaded the latest ISO from Microsoft, stuck it into MDT, added some tasks into the Task Sequence, and attempted to build a VM. This is where the problems began. To cut a long story short:

1, You'll need to upgrade MDT and ADK, along with the Windows PE addon, to the latest version to be able to deploy Windows 10 2004.

2, The latest version of MDT is slightly broken, and will identify BIOS machines (or version 1 VMs) as UEFI, and thus the Failure (5616): 15299: Verify BCDBootEx issue.

There are two fixes, one is a script that needs to be placed into your Task Sequence - Video here:

Script can be found here: https://github.com/DeploymentResearch/DRFiles/blob/master/Scripts/FixUEFIDetection.wsf

The other is a direct fix from Microsoft, which is probably the best bet, https://support.microsoft.com/en-us/help/4564442/windows-10-deployments-fail-with-microsoft-deployment-toolkit

I can confirm the script in the first link resolved my issue. I'm hoping the fix from Microsoft will resolve it permanently, without the need for a separate task in each sequence!

Initial testing shows that the first fix works, the one from Microsoft didn't. I may have missed something, but for now I'll continue using the script.