The Great Third-party solution of KDETools to OST to PST Migration for migration data from OST to Outlook format without needed MS Outlook installing you easily run to Convert OST to PST Outlook format.  This software provides best opportunity to select single or multiple OST items by Batch Conversion Option to transfer files from OST to PST Outlook (2019/2016/2013/2010). 

best free ost to pst converter