Win10 Pro machine decided to install Home instead...

My Dell XPS 8920 came with Windows 10 Home installed. After a few months, I purchased a W10 Pro license for the machine, and have clean installed Windows several times in the year since. Today, after installing two additional memory modules, and re-flashing the bios to the latest version, I clean installed again, and found to my surprise that Windows 10 Home was installed and activated. I was able to activate Pro by changing to the generic product key for Pro, but I am still puzzled.

What is the likely cause of this?

You said you purchased a Pro licence. Try changing the licence key to that again and it should upgrade to the Pro version you bought. It seems the MS activation servers are confused since you have two valid Windows versions (Home & Pro) for your current PC configuration.

mta3006 said:

My Dell XPS 8920 came with Windows 10 Home installed. After a few months, I purchased a W10 Pro license for the machine...
...I clean installed again, and found to my surprise that Windows 10 Home was installed and activated. ... What is the likely cause of this?

All machines built for and supplied with an OEM install of Windows 8 or above have the OEM key embedded in the firmware (rather than a CoA sticker as was used in Win7). When you do a clean install of Windows 10 Setup.exe detects this key and uses it to skip asking you which edition to install (Home or Pro) or asking you for a key. Your key in the bios was for Home, so that's what it installed. The PC has an existing digital license for Home so it activated.

Since your upgrade your machine now has digital licenses for both Home and Pro on Microsoft's activation servers, so either one will activate. As you say, it's easy to upgrade from Home to Pro using the generic Pro key, your existing Pro digital license allows that.

There are ways to modify the install media to force a clean install of Pro (search for threads on ei.cfg) but the easiest way is to let it do its thing and upgrade to Pro when done. I have a PC in a similar situation, a Pro digital license on a machine with a W8.1 Home key its the bios.

If you want to investigate, ShowKey Plus can tell you your embedded key.

ShowKeyPlus - Windows 10 Forums

@Porthos, @Steve C, @Bree,


Many thanks for the responses; I had a feeling it had to do with the BIOS defaults reset and the BIOS re-flashing and possibly the memory upgrade causing MS to see this as a new machine. I did change the product key to the default Windows 10 Professional key I had gotten from ShowKeyPlus right after I purchased the Professional license, but the upgrade/install/activation changes that took place after that took about 15 minutes and a few extra restarts. Not that that would be such a terrible problem, but every other clean install I have done previously both installed and activated the same product version as was active on the machine before, without having to change the product key, and go through extra upgrade/installation phases. (same with my HP laptop)

As I will probably do another clean install on release of 19H1, I'll see what happens then. I wish PC OS management wasn't so "interesting"; I would much rather have it be predictable and boring...

mta3006 said:

I had a feeling it had to do with the BIOS defaults reset and the BIOS re-flashing and possibly the memory upgrade causing MS to see this as a new machine.

MS don't say exactly how they calculate the hardware ID of a machine, but they have said the hard drive isn't part of it. The RAM upgrade shouldn't make a difference either. The most significant factors seem to be the motherboard and cpu's ID and/or serial numbers.

As I will probably do another clean install on release of 19H1, I'll see what happens then. I wish PC OS management wasn't so "interesting"; I would much rather have it be predictable and boring...

I expect the setup for 19H1/1903 will work the same way as previous versions. For an in-place upgrade it retains whichever version you had, but for a clean install it will read the key from the bios, in your case that's a Home key. You can add a PID.txt file to the install media to force it to always install Pro. See...

Installation does NOT ask for key during install Solved - Windows 10 Forums

With you regularly performing clean installs see if you can perform a reset remove files for the next one followed by an in place upgrade repair. That may get you a clean install equivalent and allow you to maintain Windows 10 professional.

Reset Windows 10 | Tutorials
Repair Install Windows 10 with an In-place Upgrade | Tutorials

I am waiting for 19H1 to do a new clean installation. I don't remember ever having to change product key after a clean install of Professional before (my desktop XPS 8920 came with W10 Home installed, I upgraded in November 2018, much later than I remembered when I made the OP). But I am sure all my clean installs of W10 Home and Professional went without key changes on my HP ProBook 4540s which shipped with W7. I usually cut off Internet connection prior to clean installs, so I can apply any CUs before Windows Update starts using up my limited home data, then connect and immediately sign in to Microsoft Account to allow activation to take place.

I'll see what happens when 19H1 gets here....

mta3006 said:

I am waiting for 19H1 to do a new clean installation. I don't remember ever having to change product key after a clean install of Professional before (my desktop XPS 8920 came with W10 Home installed, I upgraded in November 2018, much later than I remembered when I made the OP). But I am sure all my clean installs of W10 Home and Professional went without key changes on my HP ProBook 4540s which shipped with W7. I usually cut off Internet connection prior to clean installs, so I can apply any CUs before Windows Update starts using up my limited home data, then connect and immediately sign in to Microsoft Account to allow activation to take place.

I'll see what happens when 19H1 gets here....

Windows 7 computers do not have product keys stored in BIOS/UEFI that can be used to activate Windows. Only computers that came with Windows 8 or later have a real product key stored in BIOS/UEFI.

NavyLCDR said:

Only computers that came with Windows 8 or later have a real product key stored in BIOS/UEFI.

Quite. A Clean install on a machine built for Windows 7 will ask you which edition to install. On a Windows 8 or later machine Setup will use the embedded key to decide which edition to install - and if that is a key for Home, that's what you'll get installed.