Grey Previews

Hi!

So recently on my desktop I keep getting grey previews. The only time I can see an image is in develop mode. I have tried uninstalling & reinstalling lightroom, updating my drivers, building previews, deleting the preview.DB folders , anything I can possibly find on Google for an answer, I've tried. Why can't I see my images!? I have to resort to my iPad as it's the only way I can view my photos and edit without struggling.