Retrieval of Lost OST Data after Deletion or File Corruption

Microsoft Outlook is a name that has been entrusted by businesses as a secure and professional communication tool. With its collaboration with Exchange Server, it proved itself a leader in the field and is still ruling as one of the best client-server messaging software deployed by organizations.

On Server, all mailboxes are saved into a provided database while individual mailbox at the client’s end gets into the OST file. Any up-dations into the mailbox at client or the server end are reflected through the process called Synchronization.

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Relationship between Server Mailbox and OST:

In simple words, it can be considered that the mailbox and its respective OST file shares a parent-child relationship. They share similar traits and are the carbon copy of each other.

When an OST file is created using the MAPIEntryID GUID of the mailbox, an encryption key is generated that is saved into the PC registry for that MAPI profile. The similar key is saved on the mailbox that is saved on the machine. In case this link is broken, the child would fail to have access to the parent mailbox.

This could happen due to various reasons. For example the OST file is tried to be opened in a different MAPI profile or the mailbox settings (like alias name, location, database etc.) has been changed. Such state of OST is termed as Orphaned.

The Vulnerability of OST on Client Machine:

The OST file of Outlook is similar to any other file saved on machine and thus it can fall prey to “N” number of hardware or software related vulnerabilities. Following this, the OST file might refuse to open and revert back with errors. The inability to open the file and have access to the Exchange mailbox & its messages end up with the query as how to retrieve lost offline storage file.

How to Restore an Outlook OST File?

Synchronization Errors:

How to Detect Sync Issues:

To verify if the actual problem occurs due to improper communication between the client and the server, check out if the items count in the folders (inbox, calendars, contacts etc.) at both end matches or not. For this, you can follow the below mentioned procedure:

  1. Open Outlook. Select the folder in OST that has to be checked, right-click on it and choose “Properties”
  2. Click on the “Synchronization” tab and under the “Statistics for this folder” option, verify the following credentials:

Last Synchronized on: Date

Server folder contains: # Items

Offline folder contains: # Items

If the numbers of items are same in the folders at both the end, it means synchronization takes place smoothly. But if not, you may find the reason and a solution in later section of this segment.

Probable Reason:

Sync problems happen when the client and the server are unable to establish a connection. In a normal situation, when the connection is established after a stop, the sync takes place automatically but it does not happen, it is recommended to try OST Integrity Checker to fix Microsoft Exchange synchronization errors.

This tool is available free of cost with the name scanost.exe and checks OST file structural issues. To use this utility, make sure that Outlook is connected with Exchange Server. Although this utility can work to detect and fix sync issues, it is unavailable for use by users of Outlook 2010 and later editions.

OST File Data is missing:

Deletion can be intentional or accidental phenomenon. If data is deleted from OST file (even permanently), it can be restored. When configured with Exchange Server, Outlook has an option called “Recover Deleted Items”.

This helps in recovering the items that have been removed from the Deleted Items folder. Reason being this folder is connected with Exchange server dumpster and thus until the deleted items are under retention period, it can be recovered.

Cannot Open/Read OST File:

OST is Orphaned: In this case, it is easy to recover the contents of an OST file if no changes its MAPI profile is done. MS Outlook is available with the option to export the Exchange mailbox as OST into PST file.

OST File is Corrupt: If the OST file is corrupt, there is no utility provided by Microsoft as a work around. Therefore, the only solution left is to rebuild the OST file, i.e. again configure the Exchange mailbox with Outlook profile. This process is simple and before executing it, makes sure that the old OST file is deleted.

However, for an OST user, there is no better solution than having an OST Recovery software because it will help to retrieve data from OST file lost due to corruption or deletion. Adding one to the toolkit can make you free from OST data loss issues as these solutions help to restore OST to PST which gives the additional facility to opening the offline storage of Exchange mailbox into any Outlook profile. Visit For more- http://www.perfect.microsoftconvertosttopst.com

  • Visit for more if unable to re-access OST files and recover straightforwardly- http://www.ostrepair.net/

  • Visit for more if unable to access .ost files into Outlook, recover and re-use safely with OST Recovery software.

    http://www.ostrepair.net/

  • Microsoft OST File Converter is a convenient utility to get back even deleted .ost items as
    developed with the advanced algorithm of OST recovery technology.

    Tryout its free app and make OST emails, notes or any folder usable-

    – > http://www.importostfiles.net/

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