I have a Macbook Pro running OSX 10.9.5. I am using Lightroom version 5.7.1. I have done all the usual things. In Disk Utility I have verified Disk Permissions and also run Permission Repairs. I have also dragged the plist to Trash and restarted my computer.
The problem happened suddenly. As double check that there is no problem with the SD cards I have successfully imported the same pictures to My Catalog on a second computer, also a Macbook Pro running exactly the same versions of OSX and Lightroom. There was no problem.
I would be most grateful if anyone at Adobe or a member of the Forum could suggest a solution. Thank You.