Lightroom won't recognize my raw nef images. I upgraded and then it would show the images. I created a collection and then went back to view the collection a few days later. No collection was there. The images are in a folder on my computer; however, I can't import them to lightroom.
Can you go to the folder in the library module and see the images?
Maybe you're running an older LR version, now. Make sure what LR each shortcut is pointing to. Do Help / System Info to find out which LR version you're using.