If the emails marked as '''SPAM''' are in a spam folder directly under your email, then that's a spam folder on the emails server and probably being marked there, on the email server, and not by Thunderbird. So you may want to go to the source of the emails and check and see if they're already marked as spam there. While there, you could '''WHITE LIST''' the specific email addresses you know are not spam, so the email server won't mark them as '''SPAM'''. Each email account provider may have different ways of setting up a '''WHITE LIST''', and you may also be able to adjust the sensitivity to the spam. For instance, some email hosts use spam filters like SpamAssassin where you can adjust setting. Thunderbird has a setting to '''Trust junk mail headers set by..." and you get to enable/disable it as well as select the type of headers it looks for. You may want to read this... docs.cpanel.net/cpanel/email/spam-filters/ But, as I mentioned, each email service will probably be different. Spammers Byte. They make us work too hard, forcing us to read through all the junk anyway, just to see if we missed something important. Good Luck!!