Try OST to PST Converter software is very easily recover corrupted OST data and convert into Outlook PST format with all Emails, Send Items, Contacts, calendar , Notes, entries, and journals. It's an advanced solution which does not harm original attributes of OST data and export OST files to different other file formats like; PST, EML, MSG and Office 365 profile. for more details please visit https://www.softknoll.com/ost-to-pst-converter/
I would like to share manual as we all as external solution. If you are technical person then you can use manual method otherwise go with external application.
1) Configure the Outlook account and click on*File.
2) Choose*open > export*from the file menu.
3) Choose*export to a file*under the*export and import wizard.
4) Select Outlook data file format .pst and click on*Next.
5) Choose the required mailbox to be extracted. Then click on*Next*to continue.
6) Browse the location to save .pst file. Click on*Finish*to complete process.
So with the help of few steps OST file can be effectively converted to PST file without any data loss.