I've upgraded to macOS Catalina (10.15) & now I have many previously created albums in Photo that are still showing as albums BUT are (mainly) empty or do not have all of the photos previously stored there present.
The photos in question are all there in 'Photos' under 'Library' but not all of them (most of them) are showing in the albums?
Only thing I can think of is that the upgrade process re: photos was interrupted somehow & it is only part complete? But I can't work out how to 'reset' this or start again.
I do not use iCloud for photos so this (I'm assuming?) has nothing to do with iCloud syncing issues.
Any ideas? Thanks