hello experts,
here im using Microsoft outlook for mails while i am formatting my system i took a backup (.pst) file and now after configuration now while i import .pst file to my outlook it says an Error report (Given Outlook.pst is not a personal folders file) i used third party software to repair my pst backup and changed read write options none solved my problem 
Help!

• Moved by Lanlan HuangMicrosoft contingent staff Tuesday, July 07, 2015 5:18 AM

Hi Leon,

This error generally erupts if the PST file header is corrupted. Since header is the most important part of PST file, Microsoft Outlook believes the whole file to be corrupted even if only header has been damaged. So, to repair your broken PST file using Scanpst.exe refer this link:  http://www.howtogeek.com/howto/microsoft-office/fix-your-broken-outlook-personal-folders-pst-file/

Here steps have been illustrated through images.
If you are still not convinced with the result then take help of any reliable third party PST repair tool.