We’ve all done it before. You sit down to log into your Windows machine, type in what you think is the password, and bang, you realize you forgot what it was! You scramble to try different combinations of letters and numbers to see what will fit, but nothing works. What do you do now?
Use the Password Reset Tool for Microsoft Live Accounts
The first (and most obvious) solution available from the outset is to use the standard password reset function available at Microsoft’s password reset website. There you’ll find three choices, and for this particular case, you’ll want to follow the “I Forgot My Password” selection if you’re attempting to recover any accounts that are tied to your online identity.
And, again, this applies to your Microsoft Account password, not a Windows 10 User Account password. The two are not equivalent.
The HowToGeek article also clearly states, as has been mentioned here already, that the use of the built-in Admin account to change a Windows 10 User Account password only works for local user accounts, not ones that were set up with a link to a Microsoft Account.
So far as I have been able to determine, and I've experimented with virtually every method that's out there, the only way to recover access to a Windows 10 User Account that was created with a link to a Microsoft Account when you've forgotten the password is with a Password Reset Disc, if you had the foresight to actually create one for that account (as they are account specific). Otherwise it's generally a "create new Win10 account [either local or linked with admin privilege], copy over existing data from account where you don't know the password, nuke account where you don't know the password." I've always found it odd that another admin on the machine can delete any account, but cannot reset the password on a Microsoft-Account-linked Win10 user account (but can for any local account).
It's all a bit weird and has increased the level of security provided purely by the password itself for a given Microsoft-Account-linked Win10 user account significantly. It also makes it a complete nightmare if you forget it and have no Password Reset Disk for the account, and most people don't.
Brian AKA Bri the Tech Guy (website in my user profile) - Windows 10 Home, 64-Bit, Version 1803, Build 17134
Memory is a crazy woman that hoards rags and throws away food.
~ Austin O'Malley