Unable to access Microsoft Account after unauthorized security changes

Question

Unable to access Microsoft Account after unauthorized security changes

LOW XIANG XIANG 0

I received official Microsoft security emails stating that my passkey was deleted and a new passkey was added without my authorization. I now receive 'We couldn't find an account with that username' when trying to sign in. I believe my Microsoft account has been taken over and the sign-in alias may have been changed. I have the original security emails as evidence.

Chris Hailes 155 Reputation points MVP

2026-08-22T05:42:43.1766667+00:00
Before anyone can suggest the right recovery steps, can you confirm whether this is a personal Microsoft account (Outlook.com / Hotmail / Live / Xbox / OneDrive) or a work/school account managed by an organization?

That distinction matters because the recovery process is different:

Personal account: recovery usually goes through Microsoft account recovery and sign-in troubleshooting.

Work/school account: the organization’s admin may need to check the account, sign-in methods, and audit logs.

Once you confirm which type of account it is, we can point you to the right next step.

1 answer

Your answer

Chris Hailes 155 Reputation points MVP

2026-08-22T05:42:43.1766667+00:00

Before anyone can suggest the right recovery steps, can you confirm whether this is a personal Microsoft account (Outlook.com / Hotmail / Live / Xbox / OneDrive) or a work/school account managed by an organization?

That distinction matters because the recovery process is different:

Personal account: recovery usually goes through Microsoft account recovery and sign-in troubleshooting.

Work/school account: the organization’s admin may need to check the account, sign-in methods, and audit logs.

Once you confirm which type of account it is, we can point you to the right next step.

Answer 1

If this is a personal Microsoft account (Outlook.com, Hotmail, Live, Xbox, OneDrive, etc.), the unauthorized passkey changes and the message saying that Microsoft cannot find the username are consistent with a possible account takeover or change to the account's sign-in information.

Since you still have the original Microsoft security emails, keep them as evidence and do not delete them.

I recommend the following:

Use Microsoft's official Sign-in Helper first to determine whether the original username/alias is still recognized.

If you cannot sign in, use Microsoft's account recovery form and provide as much original account information as possible.

Try the recovery process from a device and location you normally used to access the account.

Do not provide your password or verification codes to anyone claiming they can recover the account for you.

If you still have access to any Microsoft service that is signed in with the affected account, immediately review the security information and sign-in activity.

If the account contains important OneDrive, Outlook, Xbox, or other data, mention the unauthorized security changes and the approximate date they occurred when submitting the recovery request.

If this is instead a work or school Microsoft account, do not use the personal-account recovery process. Contact the organization's Microsoft 365/Entra administrator. The administrator can investigate authentication methods, sign-in activity, and audit logs and can help restore access.

The distinction between personal and work/school accounts is therefore important before recommending a specific recovery procedure.