This new Condition named Has Failed Emails is on the Miscellaneous tab in Search Builder. This Condition will let you find anyone that has had a failed email since the date you specify.
One use case would be to create a search to find everyone in a specific small group and add this new Condition to see who in your group has not been receiving emails. You can look at each individual's Failed Email tab to see the reason.
Sometimes the problem is just a typo in the email address, and you can easily correct it. Maybe it is a bad/old address, and you can call to get the correct one. Or it might be a Spam Block that has been placed on that email address. If that is the case, you will want to read more about how to handle those special situations. Read more..
Of course, if you are the one sending the emails, you will receive a failed email notification. If everyone manages those as they receive them, you will greatly reduce the number of people with failed emails!
Check out this new Search Builder Condition!