I am trying to transfer emails from mac mail to microsoft thunderbird in windows pc. Its not the first time I am trying to import emails from mac mail to thunderbird. Earlier it was a smooth transfer but this time the import is not functiong the way it did. I have few thousand emails that I need to transfer to thunderbird, among those emails therea re some very important emails that contain some attachments that are in few mega-bites. So how can I transfer all these emails from mac mail to thunderbird without harming these attachments?