I'm using LR 5.7 fully updated. All image previews are showing in Library module, and when I move to Develop module, the selected image shows in the central window (in loupe view) as expected. BUT if I make any adjustments - whether using presets or simply tweaking individual sliders - the image instantly disappears and the central window turns dark gray. Stranger still, the adjustments ARE being made and are listed in the history tab, and if I switch back to the Library module, the adjustments are reflected in the preview. Of course, I must be able to see the adjustments in real time as I make them in the Develop module, as I always have previously.
Anyone know why this is happening?