''The folder 'Junk-1 on ***@***.com' could not be found, so filter(s) associated with this folder will be disabled. Verify that the folder exists, and that filters point to a valid destination folder.'' Thunderbird thinks it has an invalid filter to a folder that does not exist. No, I do not have a folder "Junk-1" No, I do not have a filter that references "Junk-1" No, the file "msgFilterRules.dat" for this account does not have a reference to "Junk-1" Yes, this happens EVERY, SINGLE, TIME, Thunderbird is opened. Yes, this happens with 102.9.1 (32-bit) as it has for the last couple of years. Suggestion, since Thunderbird can not show the filter that does not exist, maybe it could DELETE the filter from where ever it a hallucinating it and move on.