Conversion of OST files into Outlook PST is really a tough task and it becomes necessary if your files have been corrupted. In this situation, you will need a converter like ATS OST to PST Converter which has tremendous advantages that help to make the conversion process simple and modest. The user can directly migrate all their database into Office 365 & Live Exchange Server.

Visit here:  https://microsoft-office.wonderhowto.com/forum/best-way-convert-ost-file-pst-file-via-using-ats-ost-pst-converter-tool-0184450/

Check out this article: Manual tricks of NSF to PST to learn the popular conversion methods of NSF to PST i.e. - Export-Import and Setting up Co-existence. Both these methods simply import all the data from NSF file into PST file format without making any changes in the original NSF file. So no needs to worry about losing your NSF file data.

Hope this will help you.