If you want to find the best tool to convert OST safely, then I can suggest FixVare OST converter that you can try. The tool can get back OST files in all possible ways, even if the directory is protected, damaged, or hidden. This online tool makes it easy, quick, and safe to move Outlook OST files to a number of different email apps, including PST, EML, Office 365, Gmail, Zimbra, Yahoo, EMLX, ICS, MSG, HTML, vCard, vCal, and other types with this app.