If your OST file gets damaged and you are looking for a tool so I suggest you ATS OST Recovery tool that is made up of the highly advanced algorithm. It is the best tool that split large files into several small files as per your need. It support MS Outlook version like 98, 2000, 2002, 2003, 2007, 2010, 2013, 2016 and 2019. It gives 24x7 technical support. Using it you can see the preview of the recovered mailbox before the conversion then save the resultant file into several interesting file formats like PST, EML, HTML, EMLX, MSG, MBOX, vCal, vCard.