When customers harvest contacts list very common that duplicates are present. To assist you, EmailsAndSurveys will flag contacts that are duplicates. A duplicate is defined as a unique phone or email address.
EmailsAndSurveys highly recommends you backup your list before you clean your duplicates!
To remove them, click on the double square next to the red trash can on the right. All duplicates will be found.
Then click the red trashcan on the right to delete the duplicates.