If you want to extract attachments from MBOX files, then I highly recommend you eSoftTools MBOX attachments Extractor Software. Here are two options available for the user: you can extract the attachments folder wise and second you can extract attachments message-wise. There is also an email filter option where you can filter emails by start to end date to extract attachments. You can choose a saving location according to you. The free demo version is available. You can extract upto 15 attachments from each MBOX file with no charges.