The best and most versatile tool for converting OST files to PST files is the SysInspire OST to PST Converter application. It can also convert OST to MSG, EML, EMLX, MBOX, and NSF files, among others. If users want to export or import an OST file to a cloud server like Office365, this software can handle it. It is compatible with all versions of Outlook and Windows platforms up to and including Windows 10. It also includes a free trial edition and a straightforward way of converting OST to PST.