Microsoft .pst file appears to be corrupt

The tool that comes with MS Office 2003 that will fix this in most cases is called "SCANPST.EXE".

Please follow the below mentioned steps to recover from a corrupt outlook .pst file. 

 First of all make a backup of the outlook.pst manually by navigating to the directory

"C:\Documents and Settings\logon name\Local Settings\Application Data\Microsoft\Outlook".

Navigate to C:\Program Files\Common Files\System\MSMAPI\1033 and locate scanpst.exe.

When you see this screen select the repair button and it will fix the .PST file.