Send & Receive Issues

How to Stop Undeliverable Emails You Did Not Send in Outlook

Ayan Masood Oct 21, 2026 868 views

Question details

The user is receiving a massive influx of non-delivery reports (NDRs) or undeliverable bounce-backs for email messages they never actually sent.

How to Stop Undeliverable Emails You Did Not Send

Product: Microsoft Outlook
Device & OS: not provided
Scenario: Trying to clean up the inbox and stop disruptive fake non-delivery notifications caused by email spoofing.
Observed behavior: The inbox is flooded with undeliverable email bounce-backs, commonly known as backscatter, due to spammers forging the user's email address in the 'From' field.

Before you start

Check your 'Sent Items' folder first. If the undeliverable messages do not appear there, your account has not been hacked and is merely being spoofed by spammers.

Solution 1Recommended

Create an Inbox Rule to Filter Backscatter Messages

Set up a custom rule in Outlook to automatically move or delete automated non-delivery reports, keeping your primary inbox clean.

These bounce-backs, known as backscatter, happen when spammers spoof your email address in the 'From' field. Because your account wasn't actually hacked, you cannot stop the spammers from forging your address. The most effective way to reduce disruption is to filter these automated server responses out of your inbox.

Open Rules Settings

Open Outlook, navigate to the 'Home' tab, click on 'Rules' in the Move group, and select 'Manage Rules & Alerts'.

Start a New Rule

Click the 'New Rule' button. Under 'Start from a blank rule', select 'Apply rule on messages I receive' and click 'Next'.

Set the Condition

Check the box for 'with specific words in the subject or body'. Click the linked text 'specific words' at the bottom, type 'Undeliverable' (and any other common phrases from the spam), click 'Add', then 'OK', and proceed to 'Next'.

Choose the Action

Check the box for 'move it to the specified folder'. Click the linked text 'specified folder', choose your 'Deleted Items' or a dedicated 'Junk' folder, click 'OK', then click 'Finish' to apply the rule.

Create an Inbox Rule to Filter Backscatter Messages

Future Protection: This rule will continue to catch fake bounce-backs quietly in the background until the spammers stop using your spoofed address.

Solution 2

Manually Delete and Wait Out the Spam Wave

Understand the temporary nature of backscatter spam and simply clear the messages manually until the spoofing stops.

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Frequently Asked Questions

Why am I getting undeliverable emails when I didn't send anything?

Spammers often forge or 'spoof' the sender address of their junk mail to bypass security filters. If they use your email address and the recipient's mail server rejects the message, the automated non-delivery report (NDR) is sent back to your inbox by mistake.

Does receiving backscatter mean my email account was hacked?

Not necessarily. If the original spam messages are not appearing in your 'Sent Items' folder, your account has not been compromised. Spammers simply faked your address in the 'From' field without needing your password.

Can I stop these messages by blocking the sender?

Blocking the sender is usually ineffective because the bounce-backs are coming from legitimate mail servers (like Google, Microsoft, or Yahoo) that are simply reporting a delivery failure. Blocking those servers might prevent you from receiving real bounce-backs when you accidentally mistype a legitimate email address. Using keyword-based inbox rules is a better solution.

Outlook & Email Problems