I have Thunderbird 115.7.0 (64-bit) installed on a PC running Windows 10 Pro. When I open an html email I can see the body of the message. When I try to forward message inline, either using the forward button in the message window or right clicking the message and selecting forward as inline, in the write window that then opens, the original message is missing, with only the ----Forwarded message---- block present. An email in text format is not affected in this way. If I select view|message body as plain text, html messages will forward okay, but obviously only as text. I have tried selecting view as simple html as well as original html, but neither work. I installed Thunderbird on another PC (which had not had Thunderbird before) and copied the profile to that and there was no problem. I could open the exact same html message, see the body and still see it in the write window that opened when I clicked forward. This led me to conclude that the problem was not in the profile folder or the messages themselves, so I uninstalled Thunderbird from the problem machine, deleted all profiles and any leftover Thunderbird files and folders and purged all references to Thunderbird from the registry. I reinstalled Thunderbird and copied back the profile that I had shown to work on the spare PC but the problem persists. I am now at a loss, other than to completely reinstall Windows and start from scratch, which is a major undertaking as I have many programs installed.