Apple Mail can store mailbox data in MBOX format, while Outlook generally uses PST for mailbox storage and import. Because the two applications use different formats, you normally need to convert the MBOX data before bringing it into Outlook. The process should ideally preserve the email folders, message content, and attachments. SysTools MBOX to PST Converter can be considered for converting Apple Mail MBOX files into PST so that the resulting data can be accessed through Outlook.