hm. file and folder are practically synonyms in English: file: "a box or folded piece of card for keeping loose papers together and in order" folder: "a cardboard or plastic cover for holding loose papers, etc."
But in Norwegian fil and mappe are not. (Fil in the sense of "information" is marked as being a computer term.) Perhaps one of the people here with the power to add things can add files as an accepted alternative for folders