The catalog is a database used by Adobe Lightroom to track image organization, along with changes to images and their metadata. It is possible to use more than one catalog as and when needed - particularly useful for professional photographers - to prevent any one catalog becoming large and slow.
I've got a Mac Pro which has historically been my only editing machine. I now have a second editor so I need to be able to edit the pics on a second mac too, a Mac mini. I know you cannot work on ...