Microsoft Outlook Express periodically compacts email to save space. You can perform a manual compaction process when required to keep the application functioning efficiently. The compacted emails for each folder are stored in a database file. You may have problems retrieving the compacted messages if the database file is damaged. Microsoft has updates available on its website to help you retrieve compacted mails in Outlook Express, and you can locate the database file in which the emails are stored or backup copies of the files. Assistance is available through Microsoft Help Line and chat support for those who have issues with using Outlook Express.

Instructions

• Launch the Microsoft Outlook Express application by clicking on the Start button from the Windows desktop and then clicking on Outlook Express from the Start menu or the Programs menu. Alternatively, you can click on the Outlook Express icon on your Windows desktop or your taskbar.
• Click on the View menu and click on Current View. Ensure that Show All Messages is checked and the Show Replies to My Messages box is not checked. Your messages might not be missing but simply excluded from your current view’s settings. If you are able to retrieve your missing messages after changing these settings, do not perform the following troubleshooting steps as your database files are not affected.
• Navigate to Microsoft’s KB918069 page with your Web browser (link in References). Outlook Express is a Microsoft product and Microsoft has Knowledge Base (KB) articles available to provide technical support for known issues with its products. KB918069 helps you to retrieve compacted emails in Microsoft Outlook Express 6. Read the entire article before proceeding.
• Download Security Update MS06-076 and the KB918766 package using the links provided on the page. Double-click on the downloaded files and follow the on-screen wizards to install the software updates. You may be required to restart the Outlook Express application as in step 1. 

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• Double-click on the Recycle Bin icon on your desktop to launch the Recycle Bin application. After you have installed the update, Outlook Express will automatically place backup copies of your database files in the Recycle Bin after compaction with a .bak extension. Right-click on a BAK file and click on Restore from the drop-down menu.
• Locate the Mail_folder_name.bak file from step 6 on your computer. Right-click on the file, click on the Rename option and change the extension to .dbx so the filename is changed to Mail_folder_name.dbx.

Restart Outlook Express. It should retrieve the compacted mails from the DBX file for that mail folder. For more assistance, contact Microsoft Help Line and the tech support executives will help you fix your problem.