Google help says ' Read receipts are not delivered in the following cases:

   The message is opened using a POP client or a Google Apps Sync client.
   The message is opened using an IMAP client, but your administrator has not configured the feature to send receipts automatically.
   The message is sent to a user through a group mailing list or alias. The message needs to be addressed directly to a user’s email address in order to receive a read receipt from that user.

Thank you for your help Matt, I really appreciate the time you took to answer my question.

As for the other question and you response, I find it interesting that your automatic assumption would be that I wanted in some way to waste your time, rather than assume that as a new forum user, I didn't know how exactly how the postings worked. Or that I was trying to explain the issue I was having in the best way possible. Perhaps I should have added to my original question, I don't know, but it certainly was not my intention to waste your time - or that of anyone else.

Hey we all get snarky..My turn. My pet hate is duplicate questions. Mostly because I really take no notice of the who. It is not relevant to me. So I actually find myself answering the same thing for the same person. And not always the wsame way as the two posts contain sufficient difference that what is right for one answer is not right for the other. Not an issue, except then I have to explain why I basically contradict myself.

Interestingly enough, people tend to think of email as a signed delivery type thing when it is really so free formed that the sender can never guarantee what happened to their mail, let alone that it was delivered.

The RFC's allow for delivery status notifications. Most servers have them turned off to control spam see http://en.wikipedia.org/wiki/Backscatter_%28email%29. Read notification likewise are controlled by the receiving client (except in corporate server situations). Thunderbird default is to ask if you want to send one. My experience is most people go look for how to turn it off after they get the first request. The real result is they are about useless as the only people who return them don't need to.

Configuring your test addresses in Thunderbird should get the request to return a read receipt, as it is a part of the header and as such mail client know it was requested. If it does not perhaps there is a bug in the software.

No worries, stuff happens.

Thank you for this explanation, Matt. I figured there was something I was missing but I had no idea what it was.