I have the latest Lightroom update, and my Folders preview plus all the thumbnails inside the albums are grey. If I manage to click on the image and modify it, then the thumbnail comes back to life. How can I fix this very irritating issue for all my thumbnails?
Thanks for sharing the info with us. Could you share a screenshot of how the images look at your end? This doesn't sound like a typical Lightroom issue, so it would be helpful for us to review the screenshot.
Also, have you tried reinstalling Lightroom to see if that helps?
You may also try resetting Lightroom's preferences back to default and see how it goes. To restore the preferences please follow these steps: