Helping people with computers... one answer at a time.
"Undisclosed-Recipients" may be placed in the To: field by mail programs or ISPs if the To: field is empty. It's not standard and not in your control.
When using BCC to send out emails from Outlook Express, the recipient should see "Undisclosed-Recipient;" in the TO field. However, the recipients in my BCC list that I sent out see my own (the sender) email instead. Eventually, it is showing as FROM: firstname.lastname@example.org, TO: email@example.com. How do I get it to display "Undisclosed-Recipients:;" in the TO field?
I don't believe that it's something you can force.
By that, I mean I don't believe the exact phrase "Undisclosed-Recipients;" is any kind of standard or something that you can put in place yourself.
I don't think it's even controlled by the sender of the email.
I'll show you what I do instead.
BCC is a way to send email to someone without their email address appearing in the To: or Cc: line. It's considered a polite way to send email to a large number of people without exposing everyone's email address. It's also often a "cover your behind" approach in business allowing you to secretly include a superior or other recipient on an email message.
In some cases, you'll want to send a message to only BCC'ed recipients. The To: and the Cc: fields of the message that you're composing would remain empty.
That's technically valid, although some email programs react differently to the lack of a public recipient.
Your email program may require that you put an email address in the To: field.
There's really no way around this. Not only is something required, but it must be an email address.
There are two ways to deal with this:
Put in an email address that you know is invalid. It has to look like a valid email address, but that's all. When you send your message, you may get a bounce for that email address, which you can ignore.
Put in a valid email address. I typically use my own. The email is From: me and To: me, with a number of BCC'ed recipients who never see any email addresses on the message except for mine.
I typically recommend the latter. It's pretty obvious that when you get a message on which you are not listed as a recipient that you - and possibly others - were BCC'ed.
If your email program does not require you to place a valid-looking email address in the To: line, then several things can happen when you send the mail:
Your email program may add the phrase "Undisclosed recipients," or something like it, in the "To:" line.
The email program of some of your BCC'ed recipients may display the phrase "Undisclosed recipients", or something like it, in the "To:" line.
The email program of some of your BCC'ed recipients may do nothing, and simply display an empty To:
Again, all of this is pretty much out of your control.
Having an empty "To:" line is actually a mark against your email when it comes to making it through various spam filters, so I'd recommend putting something there.
It's unclear if having the recipient be the same as the sender is a mark against you or not. I tend to think not, because it's common to do so for exactly the reasons that we're dealing with here.
Thus, my ultimate recommendation is to send the email "To:" yourself and BCC all the recipients.
(This is an update to an article originally published May 30, 2004.)