Since the recent update to Lightroom Classic v10, Lightroom will not open the catalog previously used in v9.4 unless I upgrade the catalog. Everytime I upgrade the catalog, Lightroom creates a new catalog file. The new catalog file does NOT have the same number of photos as the previous catalog file had. Even worse, Lightroom will not open the previous upgraded catalog file and gives me the attached screenshot. As you can see, I've been through this process a few times, now.
It appears my only option is to go back v9.4 and use the catalog I had been using before. I'm right in the middle of editing a wedding and reception, and don't have the time to fuss with whatever is going on with the new Lightroom, but I would like to know why there is a constant need to upgrade a catalog which I upgraded on the previous launch of the program. I'd also like to know why the catalog would be smaller after the update. I can add the same files in the upgraded catalog as I had in the previous verison of the catalog, and edit the photos, but when I close Lightroom, I have to upgrade the catalog again.
Well, this is the normal procedure. You have to upgrade the catalog for it to work with the upgraded application. Otherwise that would block technological improvement and innovation in the application. And yes, it gets a v10 suffix.
Have you deleted photos that were still in the old catalog, but no longer on disk?