Upgrade from Windows 8 to 10, now we can't log in

I just upgraded a laptop for a friend from Windows 8 to Windows 10. Now we are unable to log in.

Originally, the Windows 8 machine reported that there was an issue with the Microsoft account, but the user would just log in with the last password that they used. This worked and we had full access to the machine. After the upgrade, Windows 10 insists on using the Microsoft account to log into the machine. The problem is that the user hasn't used that account for a LONG time. They think that the account was even deleted/closed at Microsoft.

When Windows 10 starts, with no internet connection, it tells us we need a connection to continue. If I connect to the wifi it insists on using the Microsoft account. We try the "forgot password" link, but that wants to text to a non-existent phone number.

Is there any way to log into this machine WITHOUT the Microsoft account?

The only solution I can see is to wipe the machine clean and do a fresh install, but I don't know if the Windows 10 license from the upgrade has been activated yet.

Try3 said:

You can probably solve the problem by enabling the Built-in Admin at boot then logging in to that.
Enable or Disable Built-In Administrator account - TenForumsTutorials
- Use it to create one or two password-protected, Admin, Local user accounts to use for managing the computer. I have two - one for managing the computer, one kept unused & hence pristine for use if the first ever got corrupted.
- Use it to create a password-protected, Local user account for day-to-day computing. I suggest you make it a local account for simplicity; you can leave converting it to an MSAccount until later on {assuming that you will ever need it to be an MSAccount at all}. This ought to be a Standard account but many people use an Admin account for day-to-day working as well. I do.
- Then test the accounts work.
- Then disable the Built-in Admin again.
- Then make a new system image.

Thanks! This got me into the machine, and I can see that Windows 10 Home is activated.

Unfortunately, Windows won't let me do anything with the existing users account. It also won't let me create any accounts, complaining that the snap-in is not for this version of Windows.

I have a clone of the original Windows 8 drive on an external drive with all the user data on it. I think I will just do a clean install of Windows 10 Home, then copy the user data from the external drive. I want to be sure that the machine is stable.