Cannot Delete Blank Files

Hey friends! I have a Lightroom issue that I cannot figure out for the life of me. This all started because I wanted to clear the "All Photos" section in the catalog (admittedly let this get too high). After deleting thousands of files that have been edited, exported, delivered, etc. I am noticing a bunch of these grey thumbnail "blanks." When I click on each one, nothing happens. There is no file number. I right-click, remove photo, and nothing happens. I have spent hours looking at the Adobe community forums, but this is a lingering question that seems to not have any answers. I've tried disabling the plug-ins. I've tried removing the "Lightroom Catalog Previews.lrdata" folder. I even uninstalled and reinstalled Lightroom. Has this ever happened to anyone? Is there any way to get rid of these? It's not only driving me crazy, but I am worried that it will result in some sort of file corruption in the future. Any thoughts or advice is appreciated!!