how do I change default email on 365 account?

For a personal Microsoft 365 subscription, add your current email as an alias on the existing Microsoft account and make it the primary alias; this keeps the same subscription, files, contacts, and account settings.^1^

If you can still sign in and verify your identity

1. Open the Microsoft account Manage how you sign in page: https://account.live.com/names/manage
2. Sign in with the Microsoft account that currently owns the Microsoft 365 subscription.
3. Select Add email.
4. Add your current email address and complete its verification.
5. Beside the newly added address, select Make primary. It will become the main address shown for the account, although every enabled alias can still be used to sign in.^2^
6. Leave the old address in place until the new address works for signing in and receiving verification codes. You can then select Remove if appropriate.

Important: Removing a Microsoft-domain alias such as @outlook.com, @hotmail.com, or @live.com permanently deletes that address, and it cannot be reclaimed.^3^

If your current address is already attached to another Microsoft account, it cannot also be added as an alias to this account. Existing Outlook.com, Hotmail, Live, and MSN addresses belonging to another Microsoft account cannot be transferred this way.^4^

If the old email is your only verification method

At the verification prompt:

1. Select I don’t have any of these.
2. Enter a new email address or mobile number that you can access.
3. Follow the prompts to replace the obsolete security information.
4. Wait for the required 30-day security period before protected account changes become available.

Replacing all security information at once restricts the account for 30 days, and Microsoft Support cannot send verification codes or directly change account details.^5^ After that period, return to Your info → Manage how you sign in to Microsoft, add the current address, and select Make primary.

If you also do not know the password, use the account-recovery option described on the same support page rather than creating a replacement Microsoft 365 account. A new account would not automatically inherit the existing subscription.

Sign-in email versus billing details

These are separate changes:

• Primary alias: The main email used to identify and sign in to the Microsoft account. Changing it by the steps above retains the account’s Microsoft 365 subscription.
• Security information: Addresses or phone numbers used for verification codes. Add your current contact method separately under the account’s security settings.
• Billing or shipping address: Update this under the Microsoft account’s Billing & shipping addresses settings. A billing-address change applies to new purchases; an active subscription can continue to display the previous billing address.^6^

If this is actually a Microsoft 365 work or school account rather than Microsoft 365 Personal or Family, aliases for a personal Microsoft account do not apply. Personal and organizational accounts cannot be merged; contact the organization’s Microsoft 365 administrator to change the work-account address.^2^

References

1. Change the email address for your Microsoft account | Microsoft Support
2. Which account do you want to use? | Microsoft Support
3. Can I change the email address that is connected to my Clipchamp account? | Microsoft Support
4. "Something went wrong" with error ADDriverStoreAccessNonLocalException | Microsoft Support
5. Troubleshoot Microsoft verification code issues | Microsoft Support
6. How to change your Microsoft account name or address | Microsoft Support