Delivery Status Notifications — the “Mail delivery failed” / “Undeliverable” emails from Mailer-Daemon — can pile up fast, especially if your address is being spoofed. Here’s the honest answer on switching them off in Gmail and Outlook, and what to do instead.
Part of our complete guide, Mail delivery failed: returning message to sender. Start there if you want to understand what the bounces are telling you.
First, the uncomfortable truth
You cannot switch off genuine failure notices at the source. They’re generated by the receiving mail servers when a message can’t be delivered — not by Gmail or Outlook. Any setting you toggle only changes what your inbox does with them after they arrive.
Don’t blanket-block Mailer-Daemon. These messages are how you learn a real email to a customer or colleague never arrived. Filter carelessly and you’ll silently lose invoices, password resets, and replies.
Gmail: filter, don’t block
If you’re drowning in bounces for mail you never sent, quiet them without losing the real ones:
- Open Settings → Filters and Blocked Addresses → Create a new filter.
- In From, enter
mailer-daemon@* OR postmaster@*. - Add a keyword your real mail wouldn’t trigger — e.g. in Doesn’t have put a word from your real subjects — so genuine bounces still reach you.
- Choose Skip the Inbox and apply a label like Bounces rather than Delete, so you can still scan them.
Review the Bounces label occasionally instead of trusting it blindly.
Outlook: rules to a folder
- Settings → Mail → Rules → Add new rule.
- Condition: From includes
postmasterormailer-daemon. - Action: Move to a Delivery reports folder (not Delete).
For the “Undeliverable” reports you get from your own sending, read the reason line and code — our bounce codes guide decodes them.
The real fix: stop the flood at the source
If the notifications are backscatter — bounces for spam sent in your name — filtering only hides the symptom. Publishing a strict DMARC policy (p=reject) makes receivers discard the forgeries before they ever bounce, and the flood stops on its own. Full explanation: why you get failures for mail you never sent and SPF vs DKIM vs DMARC.
Bottom line: file bounce notifications into a folder so they’re out of the way but still readable — and fix DMARC so there are fewer of them to begin with. Never delete them unseen.