If you can't open your Personal Folders file (.pst) or Offline Folder file (.ost) file, or you suspect that your .pst or .ost data file is corrupt, you can use Scanpst.exe, the Inbox repair tool, to diagnose and repair errors in the file. Scanpst.exe scans only the .pst or.ost file, making sure that the file structure is intact. It doesn't scan your mailbox on the Microsoft Exchange server.
Scanpst.exe is installed when you install Microsoft Outlook and is located at:
drive:\Program Files\Common Files\System\Mapi\1033\
For detailed information about running the tool, see the Help file, Scanpst.hlp, at the same location.
Note Use Scanost.exe, the .ost integrity check tool, if you get error messages when you synchronize your .ost file with the Exchange server.