How can I move old Outlook Express DBX emails into Outlook PST on Windows 11?

I found DBX files from my old Outlook Express backup, but my new Windows 11 system does not open them. I need to move those emails into Outlook PST while keeping the original mail content, folders, dates, and attachments safe.

Yes, you can move old Outlook Express DBX emails into Outlook PST on Windows 11 but not through direct opening. DBX files belong to Outlook Express, so they first need to be changed into PST format.
I would start by copying the DBX folder from the old PC or backup drive to a new location. Keep the original files untouched. Old files like Inbox.dbx, Sent Items.dbx and personal folder DBX files may contain important mail records, so testing on the only copy is not a good idea.
For this Windows 11 migration, GainTools DBX to PST Converter Software gives old Outlook Express mailboxes a proper route into Outlook by letting users preview DBX emails, choose the needed file and save PST output locally.
Test the free demo first and check 10 emails from each DBX folder before converting everything.