User-Agent: Build Identifier: Mozilla/5.0 (Windows; U; Win98; en-US; rv:1.7a) Gecko/20040202 MultiZilla/1.6.1.1d In the prefs you can check "Compact folders when it will save xxx kilobytes". However the actual preference is labeled "mail.prompt_purge_threshhold". #1 suggests that it will do it without further user interaction; #2 explicitly mentions a prompt, which is in fact what happens. Would it not be better to compact folders without the prompt - since the user has already indicated that's what they want? From a useability point of view the prompt locks the system, so you lose any advantage gained from automatic download of mail at startup, and then if the folders are still being compacted the filters refuse to work. Reproducible: Always Steps to Reproduce: 1. 2. 3.

mail not filtered while compacting folders is a bug, bug 139215 *** This bug has been marked as a duplicate of 115499 ***