Lost access to mail address alias for Microsoft account - how to transfer to new?

Hello Anders, this is Manuela!. I'm an Independent Advisor and community user like you ready to assist with this.
Not a Microsoft employee.

I'm afraid to say that adding an existing Microsoft domain as an alias for another Microsoft account it's not possible.
You can review this information and more by visiting the next support article:
https://support.microsoft.com/office/add-or-rem...

If the email address you're using for both accounts are from a non Microsoft domain. You're correct, that's possible

But you can review that's stated in the article notes:

"You can't add an email address that's associated with a work or school account as an alias.

Existing Hotmail, Live, Outlook.com, and MSN addresses can't be added as aliases, and you can't add an alias that is already associated with another Microsoft account."

I do already have both a work account, at work, and a personal Microsoft account on that same email address, so it doesn't seem like this is completely true. Unless terms have been changed after I created both types of accounts.

Hi Dennis,

Thanks for reaching out to us with this issue. I'm sorry that you seem to be having some difficulty in updating your account alias. If the email address that you wish to use has already been taken by another account that you don't have access to, then you
would not be able to choose to use it as the primary alias on your existing account.

That being said, you can always use a different email address that you do have access to as a new alias (email address for log in) on your current account or create a new email address to do so. I'm including some links in this post that may be of use to
you in changing or updating your email alias or recovering your password.

Recover and reset your lost Microsoft account password

How to change the email address associated with your Microsoft account

I hope this helps out and please let us know the results!

Don't worry about your questions, all of them are perfectly valid!

Regarding the accessibility of your partner's child with a new alias, everything will be accessible. It is just another e-mail address usable to sign in to the mother's account. Everything about the Microsoft Family will stay working the same way, because it is registered to the original Microsoft Account (mother's account), and also applies to the alias.

This issue is common, but sadly it isn't possible to transfer any progress from one account to the other. What I'd recommend you to do is to create a brand new account, where he will create all of the progress for his new games. For older games, the mother's account with an alias stays signed in on the Xbox, and is accessible at any point with the aliased e-mail address. This would be the easiest way to slowly phase out the mother's account on her son's Xbox console, but still keep it available in case he wants to continue the progress on a older game. Usually, on situations like this, parents create a child account under the Microsoft Family group, which allows to manage all settings for the child's account.