''Uniquark [[#question-1267506|said]]'' <blockquote> Hi All. I'm trying to convert my many folders of mail from Apple Mail to Thunderbird. I tried the Tools > Import command with no luck. It imports exactly zero messages. It does not even ask me where to find the messages. I also tried the ImportExport addon. It works, but it requires the messages be exported as box files. I can do this easily for one or two folders, but I have hundreds of thousands of message spread across thousands of folders. Are there any other tools for importing that actually work? </blockquote> There appear to be several add-ons for importing and exporting mail messages. Have you tried the newer "NG" Next Generation Import tool? It looks as if it CAN Import: - Mbox files (including structure) - EML & EMLX files - Individual or all directory files https://addons.thunderbird.net/en-US/thunderbird/addon/importexporttools-ng/?src=search Version 4.0.1 for TB 60/ TB 68 and later. I'm assuming you've just installed TB and you are starting with a clean new profile before importing. If not: you may wish to create a new clean profile before importing all folders At Once ... https://support.mozilla.org/en-US/kb/using-multiple-profiles Let me know if this does not help.