“Mail Extractor Pro” is one of the best software solutions for Mac Mail data conversion needs. If you are moving to Windows and looking to add all the emails from Mac Mail to Windows Outlook, you would find a huge value in “Mail Extractor Pro”. It lets you convert 10 items from Mac Mail to Pst, and it will be free for 10 items each folder. If you are satisfied with the performance, you can extend that number by purchasing the full license. Here is the link for its free trial version.