Lightroom 3.6 - on some photos I get a ! mark saying there is a unknown error while writing metadata to this photo. retry? - which I do and it still will not save. No other message is displayed. I've verified there are no 'read-only' permissions on both my folder and photos as well as the catalog folder and files. Ever photo that I have noticed this on as a exif version of 0210. ( not sure if it's related or not ).