Windows 10: Upgrading from 8.1 to 1511 is not able to activate, while 10240 is

Dear all,

this error has been confirmed on 5 out of 5 systems:

We take an activated win8.1 pro and upgrade it to 1511 using the ISO (offline), but cannot activate it.
Error: the activation servers are unreachable.
If we use 10240 instead, we can activate it and then upgrade with the same 1511 version and it stays activated (again 5/5 systems)

Pretty much a bug it seems. Microsoft support was not helpful, they said, since these are non-enterprise licenses, their support is "best-effort" (which I can understand) and then they did absolutely nothing with the logfiles I sent them (which I don't understand).

So I investigated myself and in error state, wireshark shows, the servers are not even tried, no network traffic going out.

I wonder why there's no big uproar around, since upgrading offline is not too unusual since it can be done scripted and many companies will use it. Can anyone confirm that? Version here is 8.1 retail, but it is the same with 8.1 OEM. The 1511 ISO was created using the current media creation tool

:)

 

Windows 10 and a new MB

If you are able to upgrade to Windows 10 1511 which you can download and upgrade Windows 7/8/8.1 or repair upgrade Windows 10 July build (10240), then you will be able to use your Windows 7/8/8.1 product to activate.

How to install
and activate Windows 10 using your Windows 7 or Windows 8 product key

 

existing windows insiders clean install and activation

will existing insiders who flighted to 10240 over time from 7/ 8.1 and are remaining in the program be able to do a clean install/activate w/o a key. or do we have to load 7/8.1 and then upgrade/activate.