If you go to Edit > Catalog settings > General, does it show the correct path to the catalog?
And can you post a screenshot of the Lightroom window with the Catalog and Folders panels on the left expanded?
According to what you have posted, this catalog has 77 photographs in it. Does that sound right? What happens if you click on "All photographs"? Is it showing what you expect? Do you have other catalogs?
The 77 photos are the import I've done after the update. But the old ones don't show. These 77 photos were placed by LR i the same folder-structure as the old ones.
Sounds like LR just created a new empty catalog.
Go to the menu / file / open recent /
and see if your previous catalog is listed there.
Nope, no other catalog listed here.
By "created a New catalog": Do you mean that LR replaced my old one?
PS: Leaving for the Mountains now, will respond further in three weeks.
No, not replaced.
You can have any number of catalog files.
During the install, a default empty catalog is often created. Sometimes LR switches to that catalog instead of opening your old catalog.