OST to Office 365 Migration Tool is the most reliable and fast software to convert OST files into Office 365 accounts. The tool imports all items from OST files, including emails, attachments, notes, tasks, contacts, calendars, etc. Moreover, the tool has a user-friendly interface which helps in converting files without any hassle. The tool is compatible with all versions of Outlook. You can use the free demo version of the tool on your Mac or windows device.