Selecting a DDL file in my Designer's workspace results in wizard error and can't FINISH

"Provide a valid path to the DDL file to import. The supplied DDL file does not exist."

To set up, I "Exported" a model file into DDL into my workspace directory on file system, turned on "Show All File Types", then refreshed Model Explorer to verify ddl file. Then tried to Import > DDL into Relational Model.