How to reset security email after it was changed by a hacker

Hi, if the hacker changed your security email and the system asks for confirmation there, you need to initiate the security info replacement: on the verification screen, click "I don't have any of these / I can't use these methods" and follow the flow; Microsoft initiates a waiting period of up to ~30 days, after which you can enter the new email/phone number. During this waiting period, you can usually log in from devices already logged in, but don't change your settings. Once unlocked, go to account.microsoft.com/security → Advanced options, remove the attacker's email, add your contact information, enable Authenticator and save the recovery codes, then Sign out anywhere and change the password for your recovery email as well. Check Outlook for any suspicious forwarding/delegating and remove them. If it's a work/school account, contact your M365/Enter administrator: they can immediately reset MFA methods and security emails for you.