Closed LR after saving and working in the catalog. When i reopened LR, no such catalog was listed. I had to start from scratch.
I’m not sure I understand what you are saying. When you start Lightroom, it will open a catalog. Lightroom cannot run without a catalog. So what exactly do you mean with “no such catalog was listed”? Did you setup Lightroom so it asks which catalog you want to open each time it starts?
It sounds to me like you are using Lightroom Classic CC, Rob, not Lightroom CC. (You can check this by going to Help>System Info.) If I am correct: go up to File in the menu bar and then Open Recent - your catalog should be listed there. Select it and relaunch Lightroom. Once you have it back, go to Edit (PC) or Lightroom (Mac) > Preferences, and on the General tab under Default Catalog, choose this specific catalog to always load.