How to Use Scanost.exe to Fix Corrupt OST File?

One of the most widely used email client is Microsoft Outlook which provides various features over its counterparts. MS Outlook stores its database in two formats PST (Personal Storage Table) and OST (Offline Storage Table). OST allows user to work with Outlook in offline mode. It stores all offline data which has been created when the user is working in the absence of Exchange Server and hence called its local storage area. User can work on OST file and modify its content in offline mode. This OST file gets synchronized and updated automatically with Exchange server once it gets reconnected. The default system folder location to store the .ost file is –


At times while using Outlook, users find it difficult to connect to server ailing to various reasons which are intangible and unrecognized. These reasons could be any like power failure, internet failure, improper upgrade of application, abrupt system shutdown, failure in data storage devices, hard disk failure, virus attack, synchronization issues, etc. which in turn damages the OST file. Once OST file gets damaged or corrupted, it becomes impossible to synchronize properly with the Exchange Server. In such conditions, it is recommended to use the inbuilt repair tool or scanost.exe which gets downloaded automatically for free with Outlook.

Note: Exchange and Outlook users can anytime recreate the updated .ost file by deleting it from its default location on the system drive when the Exchange Server is not in connection with the Outlook application and then when it gets connected or configured with Outlook, a new .ost file will get created automatically with the updated data.

Recommended: Methods to Convert OST to PST File Manually

About ScanOST.exe Tool

Scanost.exe tool performs integrity check first and can be located at

Drive:\Program Files\Microsoft Office\Office_version

For older versions, the Scanost.exe location differs as follows:

In Outlook 2000 – C: Program Files\Common Files\System\MAPINT\scanost.exe
In Outlook 2002 – C: Program Files\Common Files\System\MAPI\scanost.exe
In Outlook 2003 – C:Program Files\Common Files\System\MSMAPI\scanost.exe

This in-built utility is also known as the “Integrity Check tool”. It does not make any changes to mailbox. It only scans corrupted OST file and mailbox and tries to restore OST file synchronization differences. It repairs the offline data file by rebuilding the header of data item and resetting the file structure. The inbuilt tool scans .ost mailboxes with log files and finds conflicts between the server and client. For executing it, the user must be connected to the Server (Outlook email client with Exchange Server).

Note: The Microsoft in-built scanOST.exe tool is available for Outlook versions up to 2007 only and not for the later versions. For other versions of Outlook, users can utilize the inbuilt scanPST.exe application to scan and repair the errors or corruptions in the .ost file as well.

How to use scanOST.exe to fix corrupt OST file?

Following steps can be followed to execute this tool:

  • Close the Outlook application if it is running.
  • Locate scanost.exe at
    Drive:\Program Files\Microsoft Office\Office_version location
  • Double click on scanost.exe.
  • You will be prompted to select a profile according to your Outlook setting. Select the profile which contains the corrupted OST file.
  • Click on Connect when you are provided with the option of Connect or Work Offline.
  • Next, you can choose all OST folders for scan or specific folder as provided in the list. If you want the tool to repair the error during scan then select Repair Errors checkbox. (On deselecting this checkbox tool will create the scan log but will not repair it).
  • Click on Begin scan.
  • The scanning of the added OST file will get started, wait until it gets completed.
    Scanost.exe to Fix Corrupt OST File
  • After sometime, the message “The scan is complete” will appear. Click OK.
  • In order to view the scan log, Open Outlook, go to the Deleted Item Folder and click on the OST integrity check.

This scanned log file available under Deleted Item folder which also consists of information that tool cannot repair. This inbuilt OST repair utility is useful for scanning and comparing complete OST data to find issues between server and client but fails to repair damaged and corrupted files.

If the error still exists then refer to this OST to PST tool. It effectively repairs all kind of OST related corruptions and extracts the data out of the file allowing users to make choice before saving to either PST or other file format. The tool is best of its counterparts and does not include any data loss risk or other kind of hassles while performing. You can try your hand on demo version which is available completely free.

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The use of scanOST.exe application for fixing corruption OST file is explained with the procedural steps mentioning its limitations as well. Then a robust tool for OST repair and conversion is also mentioned and recommended for complete repair and recovery from damaged, corrupted, inaccessible and orphaned OST files.