Hit 'Choose.' Mac Mail will import all of these folders, and when it's finished, will tell you that they are under the folder labeled 'imports' in Mac Mail, and you just have to move all your subfolders back into their main folders. Then select desktop, and the folder you dragged all of your Outlook folders into. Then select 'Files in mbox format' and click continue. Once you're done copying all the Outlook folders, open up Mac Mail.
I couldn't figure out a way to select all the folders, so i dragged each folder and subfolder from Outlook into the folder on the desktop. Click and drag the selected folder (ex: inbox folder) to a new folder on your desktop.
In Outlook, Select the folder you want to move (If there are folders within the folder, you have to select each individual subfolder, as the subfolders won't copy along with the main folder, only the messages in the folder will copy).
