User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.0; es-ES; rv:1.9.0.4) Gecko/2008102920 Firefox/3.0.4 Build Identifier: versión 2.0.0.18 (20081105) If the from name has some special characters like (á, í) when you try to reply the e-mail Thunderbird thinks there are two senders. I have made a screenshot since it is easier to see: http://img55.imageshack.us/img55/8518/thunderbirdqb6.jpg If I see the e-mail with ctrl+u I get: From: =?iso-8859-1?Q?Echeverr=EDa_Jaurrieta=2C_Mikel?= Reproducible: Couldn't Reproduce Steps to Reproduce: I have tried to reproduce it but I couldn't. I did: 1. Creating and account with a name that has special characters 2. Sending an e-mail with that account Actual Results: I get different results depending on what mail provider I use. If I use gmail, it works properly, and I get: From: "=?ISO-8859-1?Q?Gonz=E1lez_Casco,_Mar=EDa?=" If I use my business e-mail when I click reply it doesn't try to reply two sender, but it doesn't show properly the name. I get: From: =?iso-8859-1?Q?Gonz=E1lez_Casco=2C_Mar=EDa?= And a screenshot: http://img300.imageshack.us/my.php?image=thunderbird2kj8.jpg Expected Results: I expected it works in every case as it does with gmail account I have problems with my business e-mail account and with other mails that are sent to me (so it is not only a problem of my e-mail provider)