catalog won't import new photos PSE 2018

Suddenly I cannot import any new photos into my Photoshop Elements 2018 Catalog.  Before this, it was working absolutely fine.  It appears to "see" new folders and files, and asks me if I want to import them.  I indicate yes, and it looks like it is actually doing the import, but then I cannot see them in my catalog anywhere.  At the same time, PSE also stopped letting me add keyword tags to photos that were already in the catalog.  Does anyone know what could be causing all this and how to fix it?  Thanks!