This all suggests that the original message isn't formatted to comply exactly with email standards. Your tablet's email client is probably more tolerant than Thunderbird. Forwarding via the tablet most likely reformats the message and fixes up the dodgy formatting.

It's an uncommon problem but I don't think there's much you can do about It in Thunderbird. It's one of those situations where having an alternative means for reading your email is useful. Does your webmail portal do a better job with these messages?

In my experience, Apple's Mail can produce problematic messages with invisible parts, both in Thunderbird and Outlook.

Hi Zenos

It would seem from the support pages I am not the only one to experience this problem. It is not clear if they have the problem with all emails or just like me only from certain sources. Both of the sources that have affected me are from what seems to be computer generated emails from companies. I would be happy to send an example of an email which shows this problem so you maybe able to say what the problem is. From experience these companies always want to blame others so being able to tell them what is wrong does help.

Looking at the emails on a tablet or web browser has always displayed them OK so these systems a tolerant of bad implementation of the email protocol. I wonder if there is scope for Thunderbird to be more tolerant although this would go against the strong view of Thunderbird to only support accepted standards.

Incidentally if I click on the view tab in TB and chose either HTML or Simple HTML I can now see the email. I found this when I was trying to capture the message body in HTML to seen it to you as a picture. They are only invisible in the text setting which works OK for most emails.