If you look in your Account Settings you'll see that you have a 'default identity' which Thunderbird describes as 'the information other people see when they read your messages'. Below that is a field called 'Your name:' what you write in here appears in the 'From: ' field when other people receive your messages. For example, in my case I have 'John' because that is my real name: when other people get my messages it says 'From John' in their email client. But I could put anything in that field: 'From an old man', 'From a Thunderbird user' or whatever. I guess that what your friend has done is to put the smiley symbol instead of their name. So you can't fix it: only your friend can alter what is in that field.

Hello No this is not the case because I've received exacly the same message on my other machine and no problem I hear that it may be due because TB is considering the Email as "junk" mail but I don't know how to avoid that !

Hello

I think that you are right and I understand better what happen My friend probably add those Emoticons after the first messages received on my first machine Then I've installed the second one ! To fix it I just have to "Edit Contact"

Thanks for your Help