Windows 10 Supscription license (M365 E3) not Activating

"Hi Chris_Ruggieri,

sxc7886 (Occasional Contributor) mentioned you in a post! Join the conversation below:

@Chris_Ruggieri is the current Win 10 pro OS licensed and activated? I only ask because I had a similar issue when I purchased M365 E5 & saw several post similar to my issue in that in order to get the OS to activate the subscription license and migrate to enterprise you had to have a valid pro subscription for windows 10 currently activated you couldn’t just download window 10 and have it activate as enterprise when you logged in. Which was inconvenient as I was testing and had to buy a win 10 pro license"

sxc7886I've tried it both with my client's KMS activation and without.  Neither way was successful. I've also tried using the Evaluation edition, which should have provided the same results.  My client has asked me to test this out before they buy several thousand M365 E3 licenses.  If I can't get it to work or if it is this big of a fiasco to activate every one of them, then I can assure you that they will not be subscribing.  This should not be this difficult.  

Step 1: Install Windows

Step 2: Join to Azure AD

Step 3: Assign License

Step 4: It activates

End of story. We should not have to be jumping through 4 million hoops on this and I will not buy a Pro license just so that it activates.  That's insane.  Are we going to need to install Pro every single time we reimage a machine???  That's bonkers.  This should be a simple Tier 1 fix not a (what is now going on) 3 week affair.