Have you received an email that displays Undisclosed Recipients in the recipient field? Rest assured, this is not a routing error, but just a simple precaution from the sender.
If you carefully examine the messages you receive in your inbox, you will no doubt find that some mails display Undisclosed Recipients in the recipient field (often titled TO: Where To:), instead of your email address or your name. Rest assured: this is neither a recipient error or a bug. This message is addressed to you, like all those that you receive. Simply, its sender has placed all the recipients – including yourself – in “blind copy”, using the field Bcc: instead of the field TO:. As its full name suggests (Bcc is the acronym for “invisible carbon copy”), this field is used to send messages by hiding the name and address of the recipients (see our practical sheet to know everything about the fields of recipients). The sender can use it in addition to the fields To: and Cc: (certified copy, in clear), to discreetly send a copy of his message to one or more correspondent, without the main recipient knowing. And when he does not put anyone as the main recipient (field TO:) or secondary (field CC:), no name appears anywhere. Instead, we just find the mention Undisclosed Recipients which literally means undisclosed recipients. One way to guarantee the anonymity of everyone.
This kind of mention appears especially on messages sent to several “independent” people, who do not belong to the same circle or to the same organization (newsletter, press release, press, etc.), so as to hide from the people who receive the e-mail the name and address of the other recipients. Importantly, it only appears in e-mail software (so-called e-mail “clients”), such as Thunderbird or Outlook. In webmails such as Gmail or Yahoo Mail, each recipient sees their name in clear, without the mention Undisclosed Recipients, the others remaining hidden.