Open the catalogs from the file menu.
Search the catalogs with Explorer/Finder - search for *.lrcat
Yeah, did that. Searched all my hard drives. No catalog, except the ones I
backed up in June. Went with that, but very strange to have the catalogs
wiped clear. Maybe related to a change in the default lr catalog location?
They had been in appdata, but are now in Pictures
Portraits, Events, Families
The default location for the catalog has always been in the personal Pictures folder.
Some other locations have changed. I never heard of a problem that a catalog is missing after an update and I really doubt the catalog is gone.