Since Lightroom 6, whenever I create a new catalog, Lightroom asks me if I want to "synchronise" with a screen saying "Take your Lightroom everywhere".
How can I prevent that screen from appearing every time I create a new catalog?
When creating Collections, in the Create Collection dialog, deselect the Sync With Lightroom Mobile checkbox.
In an existing collection, go to space just above navigator where your name is located. In the drop menu, select the pause symbol for Lightroom Mobile Sync.