How do i find a lost email for an old Xbox account?

You can try going through the recovery tool to find the email and then you would need to reset it. There is no
way to login without the email and password.

Thanks for the answer, I lost some time trying to do what you recommended but in the end I didn't succeed, I find it absurd to have to give up my old email to join the old xbox account ... I think I'll
let my old xbox die account. Thx again.

So...How do I find the settings on my old computer. And I have to use the same "old" email in Xbox on the new computer, right? and the same MS account password?

Hi Aaron! My name is Darhyl and I’d be more than happy to help you with your query.

I'm sorry you are experiencing this with your forgotten email address from your old Xbox account.

You can try to perform the following workarounds to locate the email address according to the official Xbox website: https://support.xbox.com/en-US/help/account-profile/manage-account/forgot-microsoft-account-solution

"Go to xbox.com and try signing in with the email address that you think is associated with your Microsoft account.

If you can sign in, the email address and password you entered are valid. The gamertag that’s associated with this email address will be displayed in the upper-right corner of the screen.

If you can’t sign in, check your other email inboxes for messages about your Xbox subscription or Xbox offers. This may help you determine which email address is associated with your Xbox profile.

Note: Think back to when you created your Microsoft account. Were you using a different internet service provider for email at the time?

If you’re part of an Xbox family group, have an organizer (adult account) look up your account info with the Xbox Family Settings app.

Note: This step only works if you’re set as a member of the Xbox family group. Organizers can’t review the account info of other organizers in a group.

Steps for the organizer:

Open the Xbox Family Settings app on their mobile device.
Choose the member whose account info isn’t known.
Select the Info bubble next to the user’s gamertag.
Review the info under Account email for the Microsoft account that’s associated with their Xbox profile."

If you're able to locate the email address of your account, you can proceed with recovering it through the account recovery webform:

https://account.live.com/acsr

Thank you for your kindness and understanding! Please feel free to let me know if you need anything else.

Best Regards,
Darhyl

How to find your Microsoft account using your security information.

1. Look up your username using your security contact phone number or email address.
2. Request a security code to be sent to the phone number or email you used.
3. Enter the code and select Next.
4. When you see the account you're looking for, select Sign in.