lrc crashes shortly after starting

Steps to reproduce:  Try to Open LRC

Error Message:  Lightroom encountered an error when reading a catalog file and needs to quit.  Light will attempt to dianose the problem the next time it lauches.

Tried: Uninstall and reinstall

Tried:  going back to previous version

Tried:  Alt upon opening and tested integrity

My nerves are at the breaking point….I need it to work again.