Recently my back-ups starred to fail. Received message that my start up disc was almost full. Learned that I have a lot of images in my "pictures" folder. Looked online for guidance. Walked through steps to synchronize. Reviewed "orphan" images and most are blank. When I click on them LR doesn't indicate they can't be found, yet no image shows. I can see evidence these images were edited. What I wouldnt give for a friend who knows this stuff better than me! Guidance? Thank you in advance!!
What happens once your hard drive gets this full, it leaves no working room for the program to work. When i teach starting out in Lightroom it always starts out with file management. As photographers we should always have our images on a dedicated drive that does not have out Operating System on it. You operating system drive should only hold your operating system and programs. It is really important for this drive to be as empty as possible. So ideally if you want speed in your programs make your operating drive never be fuller than 50% or ideal is around 25% of its capacity. If you would like to read and understand drives, speed and usage check out this site https://www.softraid.com/ Read their technical info about drives and how much they slow down as they fill up.
The solution for your problem is to either get a external drive or add a additional drive to your Computer. Than copy all of your picture folder over to new drive. Also copy over your lightroom catalog to this drive. Also try to clear off your operating drive as much as possible, in other words trash or copy all other files off of this drive that is not a program. Than once you trash all of these backed up files and empty your hard drive you well get Lightroom to operate correctly again.