There is a tool called "Moon Shadow Foxmail Mail" that converts each letter in the Foxmail mailbox to a separate EML file to complete the bulk mail export. But Thunderbird did not provide a function of the massive EML format mail, which can only import Outlook, Nescape or mailbox files. So we need to turn it with Outlook Express.
From the resource manager, you can import the EML file into the Outlook Express mailbox in Outlook Express from the Explorer. This allows you to import this Outlook Express mailbox in Thunderbird to achieve bulk conversion.
Finally, the "Compact" of Thunderbird's mailbox file will reduce the extra space occupied by the message.
