LR inexplicably stopped allowing me to move images direct to PS to edit. I updated PS, still no joy so I've updated LR from Classic v6. Now getting the message in the title and cant find anything online other than others with the same problem but no solution.
In order to help you better we need more information:
Operating System Version Number Lightroom Version Number (Help>System Info...) Photoshop Version Number (Help>System Info...) Step by step instructions for how you are 'moving' the images from Lightroom to Photoshop.