Here is one of the safest and reliable solution that will help users to export multiple PST files to Office 365, the DRS PST File Converter is easy to use and even non-technical users can easily run the tool, users can try the demo version that allows to save 50 emails per folder for free.

DRS OST to PST Converter is an advanced solution to convert OST to PST along with other saving options such as EML, MSG, MBOX, PDF, HTML, Gmail, Yahoo, Office 365, Thunderbird, etc. The user is able to open corrupt OST file and convert it to PST.