Early Music Lover wrote:
In Lightroom 5, there was a way to get the catalog to create a second backup of the catalog file somewhere else.
I don't think this is correct. There was never a way to do this from Lightroom.
If you want a 2nd backup of a catalog, you can make a copy in your operating system and/or use a cloud backup service.
My issue with the make a second copy is that window is used during the import process so I don't think any changes you make to the files later on would reflect that 2nd copy.
Lightroom never changes your photos, your changes are stored in the catalog file, so if you make regular backups of the catalog file, and you make backups of the photos once, that is sufficient.