MacSonik Maildir Converter for Mac appears to be a strong choice because of its compatibility features and ability to prevent data loss. If I ever need to convert Maildir files, I'll remember this. Using this utility, you can convert Maildir files in bulk on Mac OS with attachments. Several email programs, including Office 365, Gmail, AOL, Hotmail, Yahoo Mail, and Thunderbird, can export Maildir files. There is no possibility of data loss during the conversion, and the tool is completely dependable.