I am dealing with a mailbox migration task and need some guidance. I have a large number of MBOX files exported from an old email client, and now I need to convert them into EML format so they can be imported into another application that does not support MBOX directly. I tried a couple of manual methods, but they were either too slow or caused formatting issues. Some emails even lost attachments. What is the easiest and most reliable method to convert MBOX to EML?