To make txt, xml, htm and other text-like attachments show inline, toggle mail.inline_attachments.text to true in Config. editor (under Settings/General) and see if that helps with messages sent through Exchange servers.

Thanks for the reply, I did find that toggle suggestion in support forum shortly after posting this question, and yes it has worked to get the email body text back in the email, which is great but now the email is still incomplete in that it does not list, reference or display the attachment in the message at all.

So if someone embeds several files such as pdf's and comments on each its a guessing game on which belongs to each comment, the pdf's will all be there in attachment list... At the very least showing the file name would work, a preview that can be clicked to open attachment better, displaying the pdf in message window with message body text would be perfect.

Is there a way to improve this ?

TB doesn't display embedded pdf in the message body, just as it doesn't allow pdf to be embedded in composed messages. I'm not aware of any mail client that does. But if attachments are not shown in a list at the bottom, try toggling mailnews.display.show_all_body_parts_menu to true in Config. editor to show All Body Parts in the View/Message Body As menu. This sometimes helps with messages sent from Apple Mail, apart from whether they are sent through Exchange.

Thanks for your help again, I have checked that to true however emails still look the same, the attachment do show up in attachments pane, but are not in email body anywhere.

The AT000*.htm file name is in the body with a line in the order it appears, just need the attachment that triggered that to be listed there too.

Remember, if the htm file has an embedded pdf, it will not be displayed inline in TB. Maybe opening an htm file in a browser will show more info.

No the htm file does not have an embedded pdf, it just purely the body text chopped up after each embedded file.