After trying many tools to Convert OST to Outlook Office 365 Software. I suggest to you eSoftTools OST to Office 365 Converter tool will simply repair the corrupt OST file and offers to convert it to Office 365 Outlook and other file formats such as EML, MSG, HTML, MBOX, and EMLX, together with all of its inner database objects such as emails, calendars, contacts, journals, tasks, notes, appointments, and more. You can export OST files to Window Live Mail with selective 25 items without any charges.
Read More:- Convert OST to Outlook Office 365 Software
If you are looking for the well known method then I suggest you use this PassFixer OST to PST Converter software for the perfect conversion of OST file into Outlook PST format and in 10+ more formats. That can never harm your previous database while showing the result of OST files. It has many helpful features such as multiple naming options, mass conversions, recovery of damaged OST files, etc. It can easily break a large number of PST files into small formats
Read More:- Conversion of OST file into Outlook PST