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How Scanpst.exe Tool Works?

How Scanpst.exe facility works?

Before using Scanpst.exe facility, one should know how exactly it works. PST file comprises of sub folders and different messages. When Outlook creates PST file for the first time, it also includes table into it. This table is updated with information for each folder and subfolder as well. It also helps you in knowing information about each message stored in the folder. Each row in PST file contains information about a folder, message, and subfolder. Here subfolder refers to Inbox, Contacts, Calendars, and various other subfolders created in PST file.

Each email account, there is one PST file automatically created. It is possible to configure more than one POP3 account to the single PST file.

When you initiate using Scanpst.exe facility, you will find that this application check the folder in PST file and makes comparison with the contents in PST table. It assures you that each folder, subfolder, and message has a proper formatted entry in PST table. If there is entry but not entered then Scanpst.exe corrects the format and if there is no entry then Scanpst.exe corrects the format.

Location of Scanpst.exe tool is:

Outlook 2013:

  • 32-bit Windows --- drive:\Program Files\Microsoft Office\Office15
  • 64-bit Windows --- drive:\Program Files (x86)\Microsoft Office\Office15
  • 64-bit Outlook --- drive:\Program Files\Microsoft Office\Office15
  • Click-to-Run --- drive:\Program Files\Microsoft Office 15\root\office15


Outlook 2010:

  • 32-bit Windows --- drive:\Program Files\Microsoft Office\Office14
  • 64-bit Windows --- drive:\Program Files (x86)\Microsoft Office\Office14
  • 64-bit Outlook --- drive:\Program Files\Microsoft Office\Office14


Outlook 2007:

  • 32-bit Windows --- drive:\Program Files\Microsoft Office\Office12
  • 64-bit Windows --- drive:\Program Files (x86)\Microsoft Office\Office12


Outlook 2003:

  • 32-bit Windows --- drive:\Program Files\Common Files\System\MSMAPI\<locale ID>
  • 64-bit Windows --- drive:\Program Files (x86)\Common Files\System\MSMAPI\<locale ID>


Outlook 2002/ XP:

  • drive:\Program Files\Common Files\System\MAPI\<locale ID>scanpst.exe


Outlook 2000:

  • drive:\Program Files\Common Files\System\MAPI\NT\scanpst.exe


Outlook 97/ Outlook 98:

  • drive:\Program Files\Common Files\Windows Messaging\scanpst.exe


What Does Scanpst.exe Does?

When we run this utility on a PST file, it performs the following operations:

  • It thoroughly examines the directory structure of PST file along with its header items and recovers item (s) and folder (s) from it. If the data is recovered, it means the application has discovered the problem and trouble-shoot it.
  • It tries to turn an executable file into PST file. Say, there was an executable file with name “extra.pst”; the inbox repair tool will make an attempt to make it a mountable personal storage folder.


How Does Scanpst.exe Works?


  • This utility corrects the internal data structure of PST file. Means, the B-Tree structure holding data or the reference counts are examined and if necessary, repaired. These are basically the low-level objects of a file and have nothing to do with the upper-level structure of the PST file that comprises off calendars, emails, contacts etc.
  • While analysis, if the application finds any block of table or file structure corrupt, it just removes it.  If the particular block comprises of crucial data/items of Outlook, it will be eliminated. However, this happens in very rare situation but this could be the most appropriate decision that application could take at the provided situation.


How Does Scanpst.exe Acts on a Folder?


  • It assures that every mail or the subfolder exists in the system by analyzing row of every table. If the mail or sub-folder is missing, the application eradicates the row from table.
  • If the validation process does not work, the mail or the folder is marked as damaged and thus it is removed from the table. Consequently, it is deleted PST file.
  • If the validation process executes successfully, the application examines the consistency of restored mails with tables.


So, this was all about the free utility by Microsoft to troubleshoot Outlook errors.