Upgrade a brand new Windows 11 Home to Pro (without leaving the out-of-box experience and without logging in with a non-corporate account) - Super User

1. Choose language, keyboard layout, device name etc.

2. Once you hit the login screen, press shift + F10 to open CMD. Technically you can open CMD while it's installing Updates but I don't recommend this because it will restart without warning and might interrupt the following process.

3. Run slui.exe /upk. This is not always necessary but I suspect sometimes the Home license will be installed and needs to be removed first. Doesn't hurt to do anyway.

4. Run changepk.exe /ProductKey <Your product Key> It will say it failed but ignore it.

5. Restart

6. It's now Windows 11 Pro.

EX.

• Running changepk.exe /ProductKey VK7JG-NPHTM-C97JM-9MPGT-3V66T (Key for Windows 11 Pro) brought up the "Preparing for Upgrade" dialogue but then failed with Error Code 0x80070490

• I also tried slmgr.vbs /ipk VK7JG-NPHTM-C97JM-9MPGT-3V66T. This errored with 0xC004F069 and said to run SLUI to get full details. 

• I ran slui.exe 0x2a 0xC004F069 and it said 

• However, I then ran slui.exe /upk to uninstall the Product Key, and then tried changepk.exe again, after rebooting the OOBE was now for Windows 11 Pro and I could create a local user and domain join.