Follow the following steps to repair your outlook pst file.
Step 1 : Close Microsoft Outlook and Start the Inbox Repair Tool
Search for scanpst.exe on your computer and double click on it.
step 1 (a):
If you cannot find scanpst.exe search for it using windows explorer.
Goto Start > Run > cmd
On the command prompt window :
dir scanpst.exe /s/a
Check the path : in this case
c:\program files\Microsoft office\office 16\scanpst.exe
Note: office 16 will be replaced by your office version eg. office 12, office 13, office 14, office 15.
Step 2 : Repair your .pst file
In the Inbox Repair tool, type the path and the file name of your personal folders (.pst) file or click Browse to locate the file by using the Windows file system, and then click Start.
Step 3 : Recover Repaired files