I wanted to migrate my OST files to PST for a long time, so I downloaded eSoftTools OST to PST Converter Tool from Google and tried it. I also tried its free version. It is very useful to use its features. I used this solution and got really great results. So you should also download and try it now.
To migrate Outlook OST to PST, you can use MacMister Mac OST Converter. It is one of the best and reliable solution to convert countless OST files to PST files at once including all mailbox items such as emails, contacts, tasks, calendars, journals, etc. It also keeps all email details and folder layout during the conversion task without any modifications. Download a free demo pack of the app to check out the program working performance.