Consider using the SysInspire OST to PST converter software. The majority of users use this tool because it has the most useful features, such as email filtering and bulk conversion. This tool's interface is also very straightforward and user-friendly. It converts Outlook OST files to PST and a variety of other file formats, including HTML, MSG, ICS, MBOX, Zimbra, vcard, Gmail, Office 365, Gmail, EML, and EMLX. It offers a 30-day money-back guarantee as well as technical support. Download the free demo version of this tool from SysInspire's official website.