OST File is a crucial part of the MS Outlook as it stores all the data of the MS Outlook including emails, messages, notes, posts, attachments, calendar, contacts, etc. This file sometimes got corrupt by some unknown or known reasons. In order to recover the data from corrupted PST file, OST to PST Conversion is the best option out there.
Still, you need more help then here's the complete step about DataRecovoHow to Convert OST to PST.

To get more information regarding a different error in Outlook, visit here: http://www.datareovo.com

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Mac user can use another software which supports all versions of Mac operating system. Mac OST to PST Converter is suitable for converting OST files into PST in Macintosh. This Tool is the perfect solution for conversion of Outlook OST file into Outlook PST without any data loss. For fast and quick conversion, download Mac OST to PST Converter Tool. This software allows users to convert more than one OST file on a single click only with important attachments. It supports all Mac OS versions like 10.6, 10.10, 10.11. This software easily recovers corrupt OST file.

For more info visit here:- https://www.toolscrunch.com/mac-ost-to-pst-converter.html