This article (final para) stresses that email providers have a lot of leeway in how BCC is implemented: http://kb.mozillazine.org/BCC Have you checked that your provider hasn't changed their practice recently? (I'm not saying that the problem doesn't lie with Thunderbird, of course; I'm just suggesting that you check with your provider first.)

I am using MSN as my mail provider. How does one go about checking with a provider to see if anything has changed. Who would I contact at MSN? At Thunderbird? If I send a BC message through outlook it seems to work find. Is there someone at Thunderbird who can check out this problem? It is affecting their product.

Start Thunderbird with add ons disabled. You can do this from the Help Menu. If that helps you need to figure out which add on is causing problems.

I disabled all add ons and retested sending an email. They still are showing email addresses. I checked back to the last time the BC worked and looked at the sent file: the Email copy there shows NO names or addresses. However when I look at this test email, I just sent, in the sent mail file: Both names and addresses show. I would think that is telling me the problem is in Thunderbird and not with another mail service.

Are the addresses in the composition window listed on one line and separated by anything besides commas, e.g. semi-colons? Or, are you pasting the addresses from another application?

I have groups set up in the address book. When addressing the email, I use the drop button, Click Bcc and start typing the name of the group, and then select the group from the list presented to me by the Thunderbird address book. Hit return and start typing the next group name, then select the name of the second group from address book and hit return for another BC line. This is the same thing I do when sending to individuals, except I start typing their name.

Each name appears on a separate Bcc line. If it is an individual's name that persons' email address is shown enclosed by < >. If it is a group, the group's name is shown enclosed by < >.

You will see Bcc'd addresses in the copy in your Sent folder. That's by design. The question is whether or not your correspondents see them also. You appear to believe that they do.

But I wouldn't expect Thunderbird to be showing you the individual addressees named in a Mailing List. If your Lists are being expanded then something else is going on.

I agree, the mailing list emails are being delivered with all of the names and addresses even though they are being sent Bcc. Now how do I correct it, or do I have to change software? I have 6 separate groups set up representing approximately 100 people. The last time I sent out my mailing all of names in each group were visible the each respective group.

Where do I go from here?

Until a solution is found, I would recommend you try 'Mail Merge' addon extension. This allows you to personalise an email. You create an email template and save in Templates folder. You can then reuse it again and again to add the relevant additional content. So, only one email created by you. The 'Mail Merge' option will then create individual emails sent to a TO field.

Mail Merge can run from a comma separated .csv file which you could export an address book as .csv. It can also run directly from a TB selected address book. I use the Send Later option as it allows me to randomly check a few emails in the Outbox before sending.

Mail Merge:

• https://addons.mozilla.org/en-GB/thunderbird/addon/mail-merge/

Thanks, I guess that is a work around, however I think I will find another program to use.. Hopefully this problem will be resolved in the near future. Thanks for your solution.

dickn43 said

Thanks, I guess that is a work around, however I think I will find another program to use.. Hopefully this problem will be resolved in the near future. Thanks for your solution.

Regardless, your issue is with outlook.com or whatever name it uses this week. MSN as such has not existed for a decade,

When you log into your sent folder on hotmail/outlook.com do the BCC addresses show up there?

You are quite certain that the addresses are sent. Have you actually had anyone reply showing all the addresses? Please ask them to. Then check the message source in Thunderbird for those same addresses in the BCC files of the header (CTrl+U) opens the message source.

Personally I do not believe this is a Thunderbird issue at all. I even doubt it is happening, in the absence of empirical proof and some steps to reproduce that actually reproduce the problem.

I just sent a BCC message using hotmail, to gmail. When I got the message on the BCC account it showed no to: at all, the message source showed undisclosed recipients..

Some time has passed, but there have been many mentions in various forums (searched by google) about the problem with bcc emails when using outlook/hotmail. This problem appears to effect any email client except Outlook. It is possible this occured after a Windows update, as I noted one person had two computers and the updated one was effected by this issue. So it would seem that microsoft alledgedly have either a bug it is happy to allow or it's a deliberate attempt to force people to purchase and use Outlook email client. Either way MS is not exactly being compliant with accepted standards. This seems to only effect outlook/hotmail accounts. So I would suggest you send using a different server eg: gmail.

If you are looking for a different email client then you only have the option of Outlook. Of course you can complain to Outlook/hotmail microsoft, but whether they listen assuming you get through to them is another matter entirely.

Thank you for your reply. I upgraded to windows 10 and the problem was still there! I then change to Outlook and the problem has been corrected! Thanks for taking the time to help me, I appreciate it.