Trying to help someone with this situation. Been using LR 5.7 and importing. At some point the import capabilities are dimmed out. Could this be because the moved photos using the Finder rather than moving photos within LR? Is there a way to recover from this without losing photos?
If items have been moved using Finder, try right-clicking (control-click) on a folder name in the LR Library. Then choose update folder location and navigate to the new location. LR can then update the database links in the catalog.