Or how to backup any e-mail folder from Outlook Express.
Let’s say that you want to backup the “Sent Items” folder.
Open Outlook Express and create a new folder. Name it as you like. For example: “Sent items apr 2014”.
Open Outlook and check for your new folder “Sent items apr 2014”. It should be listed in the left panel and should be empty.
Browse with Windows Explorer for the folder that contains the Outlooks Express files (the .dbx files).
Rename “Sent items apr 2014.dbx” into something random.
Rename “Sent items.dbx” into “Sent items apr 2014.dbx”.
The e-mails you had in “Sent items” should now be listed in the “Sent items apr 2014” folder and “Sent items” should be empty.
You can do the same thing for the “Inbox” folder or any other folders.