Your log file is empty because it only records messages that have been detected as junk, and you say no messages have gone to your junk folder. See https://support.mozilla.org/en-US/kb/thunderbird-and-junk-spam-messages#w_training-the-junk-filter - please notice that you must mark many messages as Junk as well as many messages as NOT junk. Also, the filter is algorithmic - it doesn't remember a specific address or message as previously being junk but instead gathers characteristics and make decisions based on the total collection of characteristics. You may find in some cases the only way to "kill" certain messages is to create your own filter as mentioned at https://support.mozilla.org/en-US/kb/thunderbird-and-junk-spam-messages#w_if-you-still-have-trouble-blocking-messages Lastly, it is suggested that you enable the whitelist capability.