Install Opera 12, import from Firefox to Opera 12 via the menu there, then use the command line to enable the bookmarks importer under more tools which will be grayed out to get the bookmarks from Opera 12 to Opera 23+ (which will erase your current profile - saved bookmarks, passwords, Speed Dial, etc).That was my best attempt to help someone with importing bookmarks from Firefox, it was long after there were multiple confusing threads about importing from Firefox though so it's itself a duplicate but a better organized one if you follow the links I provided: Consider that recent topics duplication problem solved.
