To migrate MBOX to Office 365, there are a number of applications available on the internet that claim to be able to import MBOX files into an Office 365 account, but deciding which solution is the best is always a challenge for users. I recommend eSoftTools Free MBOX to Office 365 Migration Tool, which allows you to simply import MBOX files into your Office 365 account. Aside from Office 365 migration, the program can also offer to migrate some other email clients. It allows converting MBOX to PST, EML, EMLX, MSG, NSF, and other formats and importing emails to cloud platforms like- Gmail, YahooMail. Email programs that save their email in MBOX format, including Apple Mail, Thunderbird, Eudora, Seamonkey, and others, are all supported with this MBOX Converter software.