We've been advising against importing and exporting to transfer data between
the same program. It's just a good way to lose data especially if you change
the file format in between.
Assuming the original poster means their Contacts Folder ("Contact List"
could mean anything), they should just create a new Personal Folders file
(PST file) in the correct format, copy their Contacts Folder into it, close
Outlook completely, then copy that PST file and open it in the other
version.