How to change Microsoft 365 default account with no access to email associated with old account.

To change the Microsoft 365 default account on your new machine when you no longer have access to the email associated with the old account, you can follow these steps:

1. Create a New Windows User Account: Since you cannot access the old email for verification, creating a new Windows user account may help. You can do this by performing a clean boot and then creating a new local user account with administrative privileges.
   • Sign in to Windows with the new account.
   • Download and install Microsoft 365 using your new account.
2. Uninstall Microsoft 365: If you have the old account still active on the machine, you may need to uninstall Microsoft 365 completely. You can use the Microsoft 365 Uninstall troubleshooter for this purpose. After uninstalling, restart your device.
3. Install Microsoft 365 with the New Account: Once you have uninstalled the old version, log in with your new Microsoft 365 Family account and try to install Microsoft 365 again.
4. Contact Microsoft Support: If you continue to face issues, consider reaching out to Microsoft support for assistance, especially since you cannot verify the old account.

These steps should help you set up your new Microsoft 365 account on the second machine without needing access to the old email.

References:

• Microsoft 365 apps activation error "Another account from your organization is already signed in on this computer"
• Account or subscription verification errors activating Microsoft 365 Apps
• Microsoft 365 Apps activation error: "That Microsoft account doesn't exist. Enter a different account or get a new one."

Even though the e-mail address no longer exists as an actual e-mail address, see if you can use it to sign in at https://account.microsoft.com. You can add an alias, preferably a new outlook.com personal e-mail, and then use the alias when accessing your account. Alternatively, you can of course cancel the subscription and then order a new one, using an existing personal e-mail address.