LR freezes after opening catalogue

I was switching between two catalogs on my desktop when LR froze on me.  I "ended task."

I reopened LR, it opens my catalog displays Grid view with images from my catalog but is "frozen" -doesn't respond to short cut keys, mouse clicks etc.

Restarted computer -no difference

Uninstalled & reinstalled LR w/o my preferences-no difference

Tried to open back up catalog and got

I believe I have the correct permissions and made sure the file is not "read only".  Tried several other backup catalogs and got same message.

Any thoughts?

LR 8.3

Windows 10 Home 64 bit, V1809