What is the best way to migrate back to LR 3.6 from LR 4 rc2?. I have added a considerable number of images since moving to LR4.
You can select all the new imports in LR4 and Ctrl+S to write the metadata back to the files, then when you import to LR3 you'll get some of that metadata brought in, e.g. any keywords and ratings and colour labels.....but as Paige says you won't get any develop edits (LR3 won't recognise them), they'll be imported with your LR3 default develop settings.
North America
Europe, Middle East and Africa
Asia Pacific