Can't view video thumbnails. Grey with exe. type in box
When I download videos from my camcorder, they show a grey image and have green exe. written in the box. The only way I can view the content is to open it in VLC, but then I can't find VLC from the finder. Also there are tiny horizontal black lines all through the video. I can play the videos on Windows and no black lines appear. How can I view the thumbnail and get rid of the black lines?
Mac Pro