Follow the instructions below, in case they don’t effective, you have more variant with links below, found over Inet space, ultimate solution you may use only in extreme cases, when .dbx file can’t be restored by other methods
Enter the name of the corrupt folder. For example, inbox.dbx
Click [Search]
When search has found the folder, right-click on it and select rename
Call it inbox.old (where inbox is the original folder name)
When you restart Outlook Express, a new folder will be created. You will need to repeat the above steps for each folder that is corrupted. The folders used by Outlook Express are called: