Hi @MaryAnn355    Although Constant Contact has safeguards in place to prevent duplicate email addresses in your account, it's possible that a contact could receive multiple copies of an email. As previously mentioned in this thread, some of these reasons include if they are on a distribution list and how your contact is viewing the email.  With that said, how are is this contact opening the email? Are they viewing it on a desktop (Mac/PC) or a 3 rd part app on a mobile device?    If they are using a 3 rd party app we have seen cases of this being caused due to a communication error between the email client and the 3 rd party software. If your contact is using a desktop can you please share a copy of these emails complete headers? The steps to finding these message headers can be found here under the category titled Mail Servers or Firewalls. Please email this header to social_support(at)constantcontact(dot) come along with the campaign name and the email address of the contact who received it. ... View more