I saw a question recently from someone who was having trouble deleting emails from Outlook Express. That was the second time that week I’d that seen a message from someone who was having that trouble.
In both cases, they had routinely deleted emails from their Outlook Express mailboxes and emptied them from the Deleted Items folder. But, when they started checking into the problem, they found that their "Deleted Items.dbx" file had become huge.
Want to find your Outlook Express mail folders so you can back them up? They’re well hidden. Follow my guide at http://www.terryscomputertips.com/computers/outlook-express-backing-up-emails.php
The immediate fix is to find and delete the "Deleted Items.dbx" file. When you run Outlook Express again, when you delete a message, Outlook Express will create a new Deleted Items.dbx file.
The longer term fix is to recognize that there are three steps required to get rid of emails. You have to delete them. You have to empty the Deleted Items folder. But, neither of those actually takes them out of your computer (they just mark them as deleted).
The final step is to Compact the Email Folder. All of the email programs have a function to clean up their files and to delete the old, deleted files in every folder that you’ve created. Until you do this, you continue to take up additional hard drive space and you really have not gotten rid of those email.
Read how to compact email folders in my article When I delete an email, it’s gone — right?