junk mail

are they in your Thunderbird address book? is that address book selected in your account settings as a white list for junk processing? If both of those things are yes, then the issue is not Thunderbird. It might be your antivirus product of choice. Some of them consider themselves competent to mange your spam for you. Mostly poorly as they don't look at your contacts in making their decisions. It might also be you mail provider. Most have some sort of active SPAM filtering happening. Big players like Yahoo and Microsoft\Outlook\Hotmail\MSN\live refer to your contacts as a white list, but as a general rule there are no, or few, contacts in the online mail account as all sending and addressing is done in the mail client. Microsoft are doing a job of forcing all your personal data into their cloud, so the absent contacts are not as prevalent there as they used to be. Well mine are because I don't play nicely with the Microsoft Agenda for online cloud storage of sensitive data, but most folk fall into line.