Thunderbird does not use the word spam or move messages to a spam folder. That is why they use the word junk but still get blamed for this action. I suggest you look at your providers spam filtering or an spam component of your antivirus software.

Well, there is actually a folder called "spam" in Thunderbird, and that is where these emails are ending up. I have also tried to address this problem directly with my provider, but to no avail. I will try contacting their helpline.

Well you are more than likely using IMAP email and seeing the folder created by your provider. As stated before Thunderbird does not use the word spam for anything.

Airmail said

Well you are more than likely using IMAP email and seeing the folder created by your provider. As stated before Thunderbird does not use the word spam for anything.

For about 5 years, I've received daily emails from a well-known online vitamin retailer often containing discount coupons. and other useful info. For about the past month, the emails arrive at my inbox with "*** SPAM***" in the subject line preceding the retailer's own subject. If T-Bird never uses the word "Spam" for anything, who do you suppose is adding this to the subject line? Don't try to tell me the retailer is adding it.

Your email provider, your antivirus software or any other Spam software you might have on your computer. None of which is covered by this forum.

Thunderbird does not do it.

If you need further help please start your own thread. The people involved with this SOLVED thread do not want to be notified about your issue.

My apologies. Perhaps if there hadn't been a large "I Have This Problem Too" button to click below the posts, I wouldn't have been induced to question your assertion.