How to upgrade 1511 from Home to Pro?

I'm not having any luck figuring out how to upgrade from Home to Pro with an existing key.  My system has been running Home and is currently running version 1511.  I've decided to go ahead and use an existing key to upgrade to Pro.  I did a clean install, expecting to be asked to specify a version and provide a key during install, but was never asked for either.  The installer simply formatted the hard drive and installed Home and activated it, with no input from me after the install started other than agree to the terms and tell it my language.

OK, no problem I thought, I'll just go to the Activation setting and give it the new key from there.  However, if I tell it I want to change the key it comes back and says the key I'm giving it can only activate Pro and I'm running Home.  If I go the Store route and tell it I already have a Pro key, it gives me the same message - it tells me my key is for Pro but I'm running Home.  Nowhere along the way does it offer to take my key and give me the upgrade, rather it implies that I must somehow magically upgrade it myself before changing the key.  And that would be fine if I could figure out how to do that.

Anyone know how to force an install of Pro when the installer automatically installs Home with no option given to change it?

I ve upgrade Windows 10 from Home to Pro. Give me please the key. Thank You.

Go offline (using Airplane Mode) to insert the Pro

Generic key to install Windows 10 RTM

Then after it changes to Pro, go back online to insert your key in Activation settings to get the Digital License assigned.  You'll have both on that PC for it's life.

You'll need to upgrade to the latest version first.  I'd install Media Creation Tool and open it to Upgrade Now.

I'm not having any luck figuring out how to upgrade from Home to Pro with an existing key.  My system has been running Home and is currently running version 1511.  I've decided to go ahead and use an existing key to upgrade to Pro.  I did a clean install, expecting to be asked to specify a version and provide a key during install, but was never asked for either.  The installer simply formatted the hard drive and installed Home and activated it, with no input from me after the install started other than agree to the terms and tell it my language.

OK, no problem I thought, I'll just go to the Activation setting and give it the new key from there.  However, if I tell it I want to change the key it comes back and says the key I'm giving it can only activate Pro and I'm running Home.  If I go the Store route and tell it I already have a Pro key, it gives me the same message - it tells me my key is for Pro but I'm running Home.  Nowhere along the way does it offer to take my key and give me the upgrade, rather it implies that I must somehow magically upgrade it myself before changing the key.  And that would be fine if I could figure out how to do that.

Anyone know how to force an install of Pro when the installer automatically installs Home with no option given to change it?

Edited:  After Version 1803 one must go offline to Insert the Generic Pro Key to change to Pro Version: 

http://winaero.com/blog/generic-key-to-install-windows-10-rtm/

After it changes to Pro, go back online to insert the Pro key in Settings > Update & Security > Activation > Change Product Key. 

What I'd also do at this point is install Media Creation Tool from this link, choosing the button to Install Tool Now and then open the installed app and choose Upgrade This PC Now:  http://windows.microsoft.com/en-us/windows-10/media-creation-tool-install

 This is the most stable way to change to the latest version (which you need anyway) and because it reinstalls WIndows while keeping your files and programs in place, fixes most problems. It also brings all Windows Updates to date.  

If there are any hurdles during install then these steps can overcome them:  http://answers.microsoft.com/en-us/windows/wiki/windows\_10-windows\_install/overcoming-windows-10-upgrade-failures/682df9cf-aecf-4d52-8df7-19e9f8dba4cc

If these do not help then report back any verbatim error message or behavior.  

If you want to temporarily block the update then try running the Hide Updates tool downloaded and installed from here:  http://download.microsoft.com/download/f/2/2/f22d5fdb-59cd-4275-8c95-1be17bf70b21/wushowhide.diagcab

If it wont' find and hide the Update then you can set a Metered Connection to turn off Windows Updates for awhile until the version matures and you can try again using the method I suggest which always works best:   https://www.howtogeek.com/224471/how-to-prevent-windows-10-from-automatically-downloading-updates/

Almost everyone with major version upgrade problems who Clean installs the same version does not have those problems.  This Clean Install should get you past all difficulties as it has hundreds of thousands of others who have followed the steps in this link and never come back to report another problem:  http://answers.microsoft.com/en-us/windows/wiki/windows\_10-windows\_install/clean-reinstall-windows-10-upgradefactory-oem/1c426bdf-79b1-4d42-be93-17378d93e587

I hope this helps.  Feel free to ask back any questions and let us know how it goes.  I will keep working with you until it's resolved.   

________________________________________________________

Standard Disclaimer:   There are links to non-Microsoft websites. The pages appear to be providing accurate, safe information. Watch out for ads on the sites that may advertise products frequently classified as a PUP (Potentially Unwanted Products). Thoroughly research any product advertised on the sites before you decide to download and install it.