OST file helps you to work offline i.e. even in the absence of the Exchange server and stores your Outlook information since last synchronization. At times, you might encounter some error messages while synchronizing your OST with the Exchange server. This indicates the OST is corrupt and has some errors. In such cases this OST integrity tool, ScanOST.exe comes can be used to detect the errors and fix them.
ScanOST.exe is the OST integrity check tool that is provided by Microsoft Outlook to diagnose and repair the errors in your local OST file in cases of any synchronization issues with OST file.
ScanOST is the default inbuilt tool provided by Microsoft and can be installed automatically with the Outlook. It performs the basic scanning and restores the OST file structure if possible. It scans the data present on your OST file and the mailbox on the Exchange server, and then compares items and folders on both locations. If it finds any inconsistencies, it tries to fix them. It does not change your mailbox on the Exchange server.
OST integrity check tool can note all the differences and inconsistencies in a scan log so that found discrepancies and resolved issues can be checked easily. The scan log also identifies the situations that the tool could not correct and need to be fixed manually. This scan log is found in your Deleted Items folder. Any problems will be noted in a message with the Subject “OST Integrity Check.”
Location of ScanOST:
Location of the OST Integrity Check(ScanOST) tool differs from one Outlook version to other. ScanOST location for different Outlook versions is listed below:
32-bit Windows- C:\Program Files\Microsoft Office\Office14
64-bit Windows- C:\Program Files (x86)\Microsoft Office\Office14
32-bit Windows- C:\Program Files\Microsoft Office\Office12
64-bit Windows- C:\Program Files (x86)\Microsoft Office\Office12
32-bit Windows- C:\Program Files\Common Files\System\MSMAPI\<locale ID>\scanost.exe
64-bit Windows- C:\Program Files (x86)\Common Files\System\MSMAPI\<locale ID>\scanost.exe
C:\Program Files\Common Files\System\MAPI\<locale ID>\scanost.exe
C:\Program Files\Common Files\System\MAPI\<locale ID>\NT\scanost.exe
Note: Locale ID is the locale identifier (LCID) used for the installation of Microsoft Office. For Example: LCID for English - United States is 1033.
Steps to use ScanOST tool:
If you have previously set up Outlook to automatically start offline mode, then this ScanPST tool won't be able to access your Exchange server. Therefore, before you run this tool, you have to temporarily change your startup settings.
Now, all the errors will be resolved by this Integrity Check tool (ScanOST.exe), and on successful completion of the scan process, a message indicating “OST repaired successfully” will be prompted. This means that the issues with the OST file is resolved and is ready to be used again.
Click on the given link if you want to know how to repair OST files.