It shouldn't.
All it is supposed to do is to check with Microsoft websites for updates.
There is something "fishy" why you don't get to upgrade through Windows Update.
Why don't you try using the other method........
Download Media Creation Download Tool
http://www.microsoft.com/en-ca/software-download/windows10
Pick the correct bit version for download.
Run the Tool.......
you can either select
Upgrade this PC now which will begin installing, or
you can select
Create installation media for another PC which will begin downloading the ISO file to your computer.
With the ISO file in hand, you can either.............
burn it to a bootable media such as DVD or USB and use it to install, or
right click at the ISO file > click Mount > click Setup.exe.
Installation will begin.
It will allow you to keep files, settings and apps or keep nothing. Your choice.
It does not ask for product key. If and only if it does, select the SKIP option and continue.
Activation is supposed to be automatic.