I setup two computers recently.  One is an older Dell Inspiron 410 from around 2010 or 2011.  The other is a brand-new Lenovo IdeaCentre All-In-One.  For both computers, I did the same thing:

  1. Download an ISO from MSDN – see my article for Installing Windows for more information.
  2. Put the ISO on a USB drive.
  3. Told the BIOS to boot from the USB.
  4. Booted from the USB.
  5. Removed/deleted all partitions.
  6. Started installation.

In the case of the Dell, I was prompted multiple times for a product key and was asked if I wanted to install Home or Pro edition (take note that Home is pretty much Pro with locked features).  When asked for the product keys, I either clicked “Skip this step” or “I don’t have a product key”.  Windows did not flinch.  When installation was done, Windows 10 Pro edition was installed – no problem here.

In the case of the Lenovo, I was never asked which edition I wanted and was never asked to input a product key.  When installation was complete, Windows 10 Home edition was installed.  I tried upgrading it by entering my product key, but constuantly failed.  It was odd because the product key was just obtained from MSDN for multiple activation the other day.

Turns out that Windows thinks I have already activated the Home edition.  They got this impression through a “digital entitlement”, which is a method they now use to help with activations without having to enter a 25-key code.  I tried a number of different administrative commands including “slui.exe” and “slmgr.exe”, to no avail.

The solution to this problem was to use a publicly-known diagnostic Windows 10 Pro upgrade key.  This key does not actually activate Windows 10 Pro, but it does perform an upgrade of the Home edition.  When that upgrade as done, I put my activation key in again and it worked.