See https://support.mozilla.org/en-US/kb/thunderbird-and-junk-spam-messages#w_whitelisting Perhaps read about whitelisting using you address book. It is the only time Thunderbird will have any regard to the from line in an email in determining if the message is junk. You can mark the message based on the from line forever, if the message looks like spam the filter will mark it as spam. You marking the message as not spam based solely on sender is probably having the exactly reverse result, it is making the filter think spammy email text is good because you keep telling it that is so. This is especially so with politically motivated messages in the USA and marketing emails as both appear to be more interested in tracking the reader and their actions/forwards etc than in informing them of anything. So what is the email provider and how do you "whitelist the whole domain" I have no idea what this is ".@domain-name.com" you can put it in your address book, but it is not an email address so you will never get a message from it for the whitelisting code to act against it. None of the mass free email providers Yahoo, Outlook, Gmail et. al. actually offer an option to opt out of their spam filtering. Yahoo for instance will reach into any folder you have placed mail in and move it to spam, even after you mark it as not spam and place it where you want it. They require the email address to be in their address book for it to be whitelisted and again they all rely on a per address whitelist, not some domain whitelisting process. SO if Bill@example.com is in your address book, it will be whitelisted. Billy@example.com will not and @example.com will never send you mail for it to match against. The sending server will reject the email for having a bad sender format, long before it ever gets sent anywhere. Any other circumstance, especially that which you describe is an action take by your mail provider, or your antivirus product of choice. There are at least three spam filters in play with most folks email using IMAP on a windows PC. If the security package purports to protect against Scams or Spam it is more than capable of royally screwing it up. So lets start from basics as I asked earlier. I would say with a great deal of confidence that if your junk log is empty you are looking at the wrong product for the filtering that is driving you crazy. My log has mail from as early as 2010 and as late as the 26 May this year It has not filtered anything to junk in the past weeks. My spam folder on one gmail account has 69 email since the 26th May that have been placed there by google/Gmail. That does not include all accounts, just the one that gets messages from this forum. None of those message as they appear in the SPAM folder has the Red spam flag set in the list, because Thunderbird did not identify the messages as spam. Do your messages have the spam flag set and showing red, or is the flag greyed out like mine? ''<p>M [[#question-1517843|said]]</p>'' <blockquote> I've seen a few posts that protest - this is not Thunderbird's fault, it's your Email provider, but I've already crossed that one off the list as I have white listed the entire domain at the Email provider. So nothing is getting flagged from the Email provider, to hint that it might be junk. </blockquote> That is a level of confidence I simply do not share. Who is the provider? How did you implement this domain whitelist with them? What antivirus product do you use?