Here's a fact that why you should actually look beyond the Scanpst.exe for OST Repair

Outlook files are often gets corrupted due to several reasons such as dirty shutdown, virus attacks, synchronization issue between Exchange Server and MS Outlook, database unavailability, etc. To overcome such situations, Microsoft has provided its in-built utility called Scanpst.exe to their users. Although, there are few major challenges in using this utility for repairing OST files here:- http://www.apsense.com/article/why-you-should-look-beyond-the-scanpstexe-for-ost-repair.html