ライトマップのアセットをすべて削除し、ベイク前の状態に戻します
The assets are located in the folder with the same name as the scene. Only the assets with names matching the following pattern are deleted. The naming depends on the lightmap mode:
Non-directional lightmap mode:
Lightmap-#_comp_light.exr
Directional lightmap mode:
Lightmap-#_comp_light.exr
It will also clear the lightmaps array and clear lightmap indices on all objects.
Baked light probes and reflection probes are cleared as well.