Here’s a convoluted solution, in case anyone finds this:
-
Make a backup of the project, in case this all goes wrong.
-
Go to the project’s folder in Windows explorer and find the maps. Duplicated the .umap file of your map by copying and pasting it onto the desktop.
-
Open the project and in the Engine’s content browser: rename the current map, save and close the engine. (I’m not sure if you can rename the current map you have open, so you might need to open a different map first).
-
Put the copied .umap file you created back in the folder in Windows explorer. Then open the project and bake the lighting for that map.