OST to PST conversion software is a tool that allows users to convert their Outlook OST files into PST format. OST files are created by Microsoft Outlook to store emails and other mailbox data when the user is working in offline mode or is not connected to the Exchange server. However, these files cannot be directly imported or opened in Outlook. For more info visit this link https://www.sifosystems.com/ost-to-pst.php