Use this method when you are moving computers and changing mail clients at the same time.
I have the dbx files from Outlook Express. The new computer this needs to be imported to is Windows 7 with Outlook 2007. How do I manage this?
Outlook alone doesn't support importing OE's DBX files, you'll first need to import them into Windows Live Mail, then export them to Outlook.
Begin by placing all of the DBX files into a folder in your My Documents folder. Be sure to include the file called Folders.dbx.
Next, open Live Mail and go to it's File, Import menu. Choose Outlook Express as the type and complete the import wizard.
Next, go to File, Export and export to Microsoft Exchange. (Don't worry, this really means Outlook and it doesn't matter what type of email account you use.)
Select the folders to export and click OK to start the process.
Always export from Live Mail to Outlook - the received dates will be messed up if you use Outlook's Import command.
Note that this same method works with Vista's Mail client and Outlook Express - you first need to import the mail files into OE/Mail then export to Outlook. The Live Mail client can import message stores created by OE, Vista's Mail, or Live Mail.
There are utilities you can use that don't require the two-step process of importing the DBX files to Live Mail then exporting to Outlook. See Converting Messages and Calendars.
For detailed steps (and a video tutorial) see Move from Microsoft Outlook Express to Microsoft Outlook on a new computer