If you want to Convert OST to PST then you need a third party tool like this OST to PST Converter Software that easily Convert your OST emails to PST format. With this utility you can solve your OST file corruption issue and recover all deleted OST file data including emails, contacts, chats, tasks, notes, journals, appointments, etc. There is No file size limit user can easily Convert and repair their any size of OST file without file size restriction.
If you are looking for the best solution to convert OST to PST then I would suggest you MailsDaddy OST to PST Converter Tool. It is easy to use for exporting OST file into PST format even for both technical and non-technical users. This tool can quickly repair corrupted OST files.
You can convert a large number of OST files to PST and other file types, including MBOX, EML, HTML, MSG, etc. Additionally, it makes it easy for you to maintain the folder hierarchy. Here users can also directly import OST file into Office 365 and Live Exchange Server.
You can also download its free trial version in which you can convert up to 20 items per folder
For complete information, visit here: Convert OST to PST