If you want to restore a lost database of Offline OST files while keeping the files in their original form, try vMail OST to PSTConverter Software. That automatically works to assist you in recovering Offline OST file database items such as emails, contacts, chats, notes, journals, appointments, tasks, contacts, and so on in a short amount of time. The software can export items from OST files to PST, EML, MBOX, CSV, vCard, MSG, HTML, and OFFICE 365 Cloud.
OST to PST Converter is the best utility which efficiently repairs the OST file and recovers all the items of OST mailbox into PST format. This software saves the exported data efficiently from inaccessible or damaged OST files. One can export a single OST mailbox to an MS Outlook with this tool. This can also export several OST files to MS Outlook in a sole conversion cycle. This software quickly retrieves emails, contacts, calendar items, hyperlink, attached files and other data from OST files. Refer:- https://www.spikevare.com/osttopst/