I have a Mac using OS ver 10.12.5 and PS LR release 2015.10.1. When I left click on a photo and then try to use "Edit In" all I get is a greyed out list. I cannot access anything here. Any help would be appreciated.
It usually works best if both applications are open. Does it work with Cmd+E or from the menu:
Photo >> Edit In
If you are working with smart previews with the master images not available you will not be able to edit in other applications.