How to Automatically BCC an Address in Apple Mail

The Mac's Mail app keeps a copy of every email message you send in the Sent folder, but some users prefer a more permanent and regular archive of their sent messages. If you have multiple email accounts and want to use one to collect copies of all your correspondence, it's easy to BCC that email address every time you send a message.

While you can do this manually, typing an email address into the BCC field of each message, it's even easier to set up Mail to do it for you automatically. This function works if you need to automatically BCC any email address, such as your boss, on all your messages.

Here's how to set up an auto-BCC function in your Apple Mail application.

These instructions apply to the Apple Mail app version 9.3 and later.

How to Auto-BCC Every New Email

When you auto-BCC a specific email address, it will be added to every new email you send out from the Mail app. You'll use the Mac's Terminal command-line interface to create this functionality.

  1. Type Terminal into Spotlight Search to open a Terminal window.

    Opening a Terminal window with Spotlight Search
  2. In the Terminal window, type:

    defaults read com.apple.mail UserHeaders
    Type the Default Read command
  3. Press Enter.

  4. The command may return a message such as, "The domain/default pair of (com.apple.mail, UserHeaders) does not exist."

    Does not exist message
  5. If you get the message, "The domain/default pair of (com.apple.mail, UserHeaders) does not exist," type the following command, but substitute "bcc@address" with the actual email address you want to use as the automatic BCC."

    defaults write com.apple.mail UserHeaders '{"Bcc" = "bcc@address"; }'
    Defaults write command for automatia BCC in Apple Mail
  6. You're done! You've set a new automatic BCC address. Read on if your above command returned a different outcome.

    Automatic BCC has been set in Apple Mail
  7. If the "defaults read command" from Step 2 returned a line of values within brackets, highlight and copy the entire line (using Command + C.)

  8. Type the following command in Terminal (don't press Return yet):

    defaults write com.apple.mail UserHeaders '
  9. Press Command + V to paste what you copied above. The entire line should read something like this:

    defaults write com.apple.mail UserHeaders '{Reply-To = "reply-to@address"; }
  10. Close the command with an ending quotation mark (') and then insert "Bcc" = "bcc@address"; before the closing bracket (remember to type the actual email address you're using as an auto-BCC), like this:

    ‘”Bcc” = “bcc@address”; ‘ 
  11. The line now reads something like:

    defaults write com.apple.mail UserHeaders '{Reply-To = "reply-to@address"; "Bcc" = "bcc@address";}'
  12. Press Enter to submit the command.

    Final automatic BCC command
  13. You're done! You've set a new automatic BCC address.

When you set an automatic BCC using this method, you can't add additional BCC recipients to your messages.

How to Disable Automatic BCC

Use this command in a Terminal window to delete the custom headers and turn off automatic BCC emails:

defaults delete com.apple.mail UserHeaders
Remove automatic BCC in Apple Mail