Lightroom 5 suddenly shows duplicates of an external hard drive under 'Folders". It also does not show files that were previously synched to that particular external hard drive. My other external hard drives seem to be fine. I think it happened after the last backup I made, which I deleted to see if it would go back to being synched up properly. It did not. I have restarted Lightroom and my computer a few times but nothing fixes it. I am using Mac.