If the fake address appears only as the sender of messages you receive, report it as phishing and block it; it cannot be removed from your Windows 10 computer because it is an external email address.
Report and block the address
Do not reply, open attachments, click links, or call telephone numbers shown in the message.
Outlook.com or new Outlook for Windows
- Select the suspicious message.
- Select Report > Report phishing. This reports the message, removes it from the Inbox, and helps improve filtering.^1^
- Reporting does not automatically block the sender. Open Settings > Mail > Junk email.
- Under Blocked senders, enter the fake address and select Add, then Save. Future messages from that address will go to Junk.^2^
Classic Outlook for Windows
- Right-click the message.
- Select Block > Block Sender.
- Also report it as phishing if that option appears.
If the address changes with each message, continue using Report phishing rather than adding every address individually. A displayed sender can be forged (“spoofed”), so blocking one address may not stop messages sent under different fake addresses.^3^
Check whether your account was actually accessed
Because it is unclear whether you can sign in normally, test this by opening Microsoft account security directly—do not use a link from a suspicious email.
- Sign in to the Microsoft Recent activity page.
- Review activity from the last 30 days.
- Expand unfamiliar entries. If This wasn’t me is offered, select it; for other suspicious activity, select Secure your account.^4^
- Check Sent Items. Messages that are absent there were likely spoofed rather than sent through your mailbox.^5^
If you find unauthorized access or cannot sign in
Since the computer was previously compromised:
- Open Windows Security > Virus & threat protection > Scan options > Full scan > Scan now.
- After the scan finishes, change or reset the Microsoft account password.
- Review the mailbox’s connected accounts, forwarding, and automatic replies, removing anything unfamiliar. Microsoft recommends scanning before changing the password when recovering a compromised account.^6^
Only if the fake address is listed on your Microsoft account
This is different from merely seeing it on an incoming message. Sign in to Microsoft account > Your info > Edit account info. If the fake address appears as an alias, select Remove next to it.^7^
Do not remove your genuine primary address. If the fake address is not listed there, there is nothing to remove from the account—use the reporting and blocking steps instead.
References
- Protect yourself from phishing
- Block or unblock senders in Outlook
- Phishing and suspicious behavior in Outlook | Microsoft Support
- Check the recent sign-in activity for your Microsoft account
- my user name is being used to send me email - Microsoft Q&A
- How to recover a hacked or compromised Microsoft account | Microsoft Support
- Change the email address for your Microsoft account | Microsoft Support