- If you are using smart previews then it will not work.
- If the images are missing then it will not work.
- So check Lightroom if you have a exclamation mark on images or a small rectangular box on images(see screenshot)
- For missing images check this link - How to find missing photos in Photoshop Lightroom
Thanks so much for taking the time to answer. I just unplugged the drive that holds my photos from my hub, and replugged it directly into my laptop and it started working. Don't know why it stopped. Since this happens occasionally with my printer I gave it a try. Since stupid MacBook Pro only has 2 USB plugs it's a bit of juggle, but, hey whatever works. aaaargh!!!!
To all: Thanks for viewing. I replugged my "images" drive from a hub to directly into my MacBook Pro. I have not touch, jiggle or did anything to my hub. My drive has been working all week. Maybe it's tired. This is something that happens occasionally with one of my printers.