DSN or Delivery Status Notification is an automatically generated e-mail message that reports the sender that a delivery problem has occurred. It basically signifies that for some reasons, message has rebound. When it comes to Outlook personal folder (.pst) file, a user might experience unexpected DSNs for several read and unread e-mails. Such kind of notifications are the possible indications of PST corruption. Thus, to regain access to lost data, restore from backup or running the Inbox Repair Tool (Scanpst.exe) is required.

To better understand such problems, consider a scenario discussed further. When using Microsoft Outlook 2003, you start noticing some unpredicted DSNs for various e-mail messages. You observe that this problem started occurring after you installed security update 925938 and/or 929969 for Outlook.

Cause

An Outlook PST generally generates unexpected DSNs when it is damaged. That's the reason why you are recommended to backup your PST before installing any updates to avoid post-crash consequences.

Solution

The damaged PST can be repaired using Scanpst.exe tool (Outlook built-in PST repair utility). This file is a part of each Outlook Installation. Follow the below steps to run the tool:

- Locate the 'Scanpst.exe' file on the hard drive using Windows search tool or you can go directly to its standard location:

disk drive:\Program Files\Common Files\System\MSMAPI\1033

Where, disk drive is the drive letter of your primary drive, usually 'C'.

1. Double-click the file located above that starts the tool.

2. Browse to the path of corrupted PST path and click 'Start'.

3. Exit the tool when the repair finishes.

The unexpected DSNs problems should go away if the repair completes successfully. However, if the problem continues, you are strongly recommended to use a third-party Inbox Repair Tool to deal with the corrupted PST problem more powerfully.

The commercial Inbox Repair Tool is designed to meet the standard needs of an effective and easy-to-use utility. These are fully functional applications with graphically intuitive interface and thorough scanning procedure. The step by step procedure of repairing corrupted PST guides you through simple recovery.

Outlook Inbox Repair is an efficient utility that repairs corrupted Outlook PST and restores it to a new and original format pst file. The Inbox Repair Tool supports MS Outlook 2007, 2003, 2002, and 2000. With a 3-pane display, this PST file repair product comes handy with simple steps. The tool is compatible with Windows 7, Vista, XP, 2003, and 2000.