www.techzaada.com How To Undo A Sent Email In Gmail br You clicked send. Oh crap. br br When you send a no-take-backs email — maybe an admission to a secret crush, or accidental reply-all — there's an instant pang of regret. It feels like there's no going back. br br Meet Gmail's Undo Send feature, a lifesaving little hack buried in the Gmail Labs settings. It gives you a 30-second window to "undo" sending an outgoing email.