I have suffered this myself occasionally. I believe it affects only certain HTML-formatted messages. I am not sure that we know how to reproduce it at will, so we don't know quite what causes it. Do you see the contents in Print Preview? Does it print to pdf successfully? (Then you could print the pdf file.) An admittedly clumsy workaround would be to copy the message's contents (ctrl+a to select all, ctrl+c to copy), paste them somewhere else (ctrl+v) and print that. If the affected messages are formatted using HTML, you'll need to paste into an editor that can accept HTML formatting. Word would be ideal. The free utility Wordpad which came with past versions of Windows would do it - I am not sure what the equivalent is in current versions of Windows. You could paste them into a new message in Thunderbird and print that; you may need to save it as a Draft to make printing work in a fully wysiwyg manner. You may find that just saving the original message into Local Folders makes it printable.