Are you sending through an AOL or Yahoo smtp server? What is the default Text Encoding for outgoing Mail in Options/General/Language & Appearance/Advanced?

I've heard if issues like this when emails are being sent through a yahoo server. If the customer sends in windows-1252 and includes for example special punctuation characters or a non-break space xA0, the ISP doesn't correctly interpret the the message as windows-1252 but as UTF-8. In UTF-8, xA0 is not valid and gets replaced by the so-called replacement character, � (0xEF 0xBF 0xBD). Since the e-mail is still windows-1252 encoded, the recipient's client displays �.

See if this works: In version 78*: Menu app icon > Options > General Scroll down to the bottom and click on 'Config Editor' button Accept the warning In search type: mime Look for this line: mail.strictly_mime If it is set to 'false' then double click on that line to toggle the value to say 'True'

In version 78*: Menu app icon > Options > General Scroll down to 'Language & Appearance' section click on 'Advanced' to see 'Fonts & Encodings' window. Under 'Text Encoding' What are you using for outgoing and incoming mail ?