Apple Mail has been a finicky bit of software since its inception. Some love it, some hate it. One problem we've seen recently in V10 with High Sierra is that emails display [the usually] hidden HTML code. This can be frustrating. Some have 'solved' it using Apple Mail's built-in "rebuild" option, but the problem seems to return pretty quick. Here's how you can solve this issue and other weird mail issues too.
Having trouble with making the directions in a post work? just click...