"Up to date" even though I am running version 1507 (RTM build of Windows 10); how to get 1803 (Redstone 4)?

There aren't three system reserved partitions. Everything sounded OK, until you mentioned that. Try...

(a) Deleting all the partitions at that screen, until only unallocated space is left.

(b) Select the unallocated space created.

(c) Click the "Next" button.

It sounds like you manually created partitions yourself, but you really should let Windows do it.

Right, so I am back finally with news.

I'm actually smart enough to use a hypervisor especially since I finally have one useful enough to figure out what is wrong... and I would refuse to believe that my firmware is the reason why I can't update past 1607 but I have this to show so I can get some more feedback...

The one on the left is my computer which has Anniversary Update (Redstone 1). The one on the right is a virtual machine connection running Redstone 5 with no issues whatsoever. Clearly I can see that, again, the BIOS information is the most discriminatory factor for my persistent upgrade issues.

Rereading this thread, you've done so much, it will be a sin if you are not ultimately successful! But - as you said - it is a learning experience (for both of us) no matter.

That looks like version 1809 that you successfully installed into a virtual machine. It hasn't been released yet, far as I know. I don't know enough to say for sure, but I want to agree your hardware is fine for 1809. It does appear the VM uses its own BIOS, as you say. But you've upgraded the machines BIOS already to 403, 12/24/2013. It's odd your site has a different date for it, though...

https://www.asus.com/us/Tower-PCs/M11BB/HelpDesk_Download/

M11BB - Downloads

(1) Have you tried to clean install 1809 into the normal computer?

(2) Have you tried 1803 into a virtual machine?

(3) You didn't answer - when at the "choose a partition" screen, you deleted all the partitions to unallocated space. Did you then try to create partitions of your own? I think it best just to select the unallocated space & click "Next".

First of all... at the screen...

This is a completely empty hard disk drive, yeah? I want to create a partition of maximum size, so I click "New".

As you can see, it it telling me that Windows is going to create three extra partitions from the amount of space I selected. These are the three system partitions I had mentioned ambiguously prior to this point.

And also, I will try 1803 in the hypervisor first. If that works, then I will try to continue...

Yes, that "where do you want to install" picture is showing a completely empty disk. And I like seeing the word "unallocated" instead of "free" there. It means Windows is dealing with a GPT instead of MBR style disk. That's a solid indicator BIOS is set in UEFI mode & the installation media was booted correctly.

But all you needed to do there was to select the unallocated space, then click "Next". Setup would then create all the partitions necessary & give the Windows partition maximum space. But it does look like what you did resulted in the same outcome. Still - I would want to try it without clicking "New" next time. It is "foolproof" that way, Greg Carmack says in that URL I cited.

I did a BING of "initialization is unsuccessful for windows 10 setup" & came up with nothing concrete. But it sounds like a file necessary to boot is bad, maybe something on the EFI system partition. But that must be brand new since this is a clean install.

Might be a good idea to make a new Win 10 Installation media, the download might have been faulty.