Email, Messaging, & Video Calls Email Sending an Email to Undisclosed Recipients in Mozilla Protect the privacy of your email contacts by Heinz Tschabitscher Writer A former freelance contributor who has reviewed hundreds of email programs and services since 1997. our editorial process Heinz Tschabitscher Updated on April 30, 2020 Wikimedia Commons Email Yahoo! Mail Gmail Tweet Share Email All the people you know are connected by no more than one degree of separation—their connection to you. Chances are they do not all know each other directly, though. You and they might prefer for you not to share all their email addresses when you mail people as a group. It is possible to email the group while keeping all the recipients' names and addresses private in Mozilla Thunderbird. The process isn't complicated; it just requires a little advance effort to create an address book entry for Undisclosed Recipients. Create an Address Book Entry for Undisclosed Recipients To make mailing undisclosed recipients easier, set up a special address book entry in Thunderbird for that purpose: Select Address Book from the menu in Mozilla Thunderbird. Select New Contact. Type Undisclosed in the field next to First. Type Recipients in the field next to Last. Type your own email address in the field next to Email. Press OK. Send an Email to Undisclosed Recipients in Thunderbird To compose and send a message to undisclosed recipients in Mozilla Thunderbird: Begin with a new message. Start typing "Undisclosed" in the To: field. Select Undisclosed Recipients from autocomplete drop down. Turn your attention to the BCC: field. Begin typing the first undisclosed. contact that you'd like to add, and select their info, should it pop up from the autocomplete drop down. Keep going, setting each new recipient field as BCC. BCC stands for blind carbon copy, meaning it'll copy the message exactly but not allow your contacts to see who else received it. You can also use Mozilla Thunderbird address book groups to add multiple recipients in one go. When you've added all the undisclosed recipients you want in the BCC fields, write your message the way you normally would, and press Send. The recipients will see Undisclosed Recipients in the area where they normally see other recipients' names and email addresses thus preserving the privacy of all involved.