could you expand on that... why do you think they should be highlighted yellow would be a good start.

Hi Matt. Thank you for taking care. Because the other party sent the email highlighted. But I cant see.

this whole highlighted sounds like that Microsoft office highlighter which simply does not work outside of Microsoft office. Could that he it?

no. another friend works. I mixed the settings but could not fix it. Could it have happened after the last update. because it existed before.

What is your setting for View/Message Body As? If it's Plain text, highlighting won't be displayed.