the advice in the first link

http://kb.wisc.edu/helpdesk/page.php?id=3059

is good. but the instructions on the above web page are a little vague and you will save yourself some time if you carefully read the instructions that you download with the Eudora Mailbox Cleaner (I didn't - and had to do it a second time!). but when instructions were followed it was successful in importing a number of mailbox folders and sub-folders containing over 28,000 emails.

Also I first tried advice from a different page and went from Microsoft Outlook to Mozilla Thurderbird on the PC and then tried to import from Thunderbird to Mail. Three consecutive attempts failed, so not recommended.

Hope this helps...