How can I convert OST data file Outlook to Office 365? Download the error-free OST to Office 365 converter tool to perform the conversion process of OST data file Outlook to Office 365 in batch mode. All through the OST data file Outlook to Office 365 process, software includes total OST files data such as; meta properties, attachments, images, etc in secure manner. Download the free OST to Office 365 Converter edition to test its working efficiency.