diff --git a/scene/3d/baked_lightmap.cpp b/scene/3d/baked_lightmap.cpp
index 13dab2e75ad..b7b7fde2e0a 100644
--- a/scene/3d/baked_lightmap.cpp
+++ b/scene/3d/baked_lightmap.cpp
@@ -156,6 +156,7 @@ void BakedLightmapData::clear_data() {
 }
 
 void BakedLightmapData::_set_user_data(const Array &p_data) {
+	ERR_FAIL_COND(p_data.size() <= 0);
 
 	// Detect old lightmapper format
 	if (p_data.size() % 3 == 0) {