I would guess that spam fighter is non functional. At Least I hope it is. Permanently. There is a long term plan to prevent the injection of any outside code into the Mozilla platform. The basis of both Thunderbird and Firefox. Either its get into Thunderbird via an add-on using the add-on manager or it does not get there at all. The development team over at Firefox at tired of having so called security software inject unsafe and often non-compatible code into the running program and basically crashing the program, or removing what were security check to make their life easier. The current situation where code is injected into the programs is actually a huge security hole that is being closed, as are the internal access to the programs core features made available to add-ons being restricted. If the anti virus and supposed good guys can do it, so can the supposed bad guys. So the gate is being closed due to abuse and the inherent security risks they represent. Personally I have issues with this statement from their web site. <blockquote> If you receive a spam mail that is not detected, click a single button, and the spam mail is removed from the rest of the 8,968,667 SPAMfighters in 238 countries/areas in seconds. </blockquote> So if someone in India take exception to the monthly newsletter from Quilting world they click a button and more than 8 million people who may want to see this subscription newsletter suddenly do not. This would have to be the worst SPAM system since Verizon offered the same lame thing to their subscribers. It cause chaos there as folks treated unwanted and spam as exactly the some thing, with some using it as a defacto delete button. Thunderbird has a [https://en.wikipedia.org/wiki/Bayesian_probability bayseian ]junk/spam filter that actually learns what you think is spam. Although because it learn it needs 50 positive and 50 negative manual decisions before it really get any good. I find that sort of personalization comforting. I really do not want my mother and my son helping me decide what I want to see. Let alone some of the decisions others I know would be making.