diff --git a/class_layout.lua b/class_layout.lua
index 7c263a6..14c116b 100644
--- a/class_layout.lua
+++ b/class_layout.lua
@@ -18,7 +18,10 @@ local get_node_image = function(pos, node)
 	
 	-- Record what kind of thing we've got in a builder node so its facing can be rotated properly
 	if minetest.get_item_group(node.name, "digtron") == 4 then
-		local build_item = node_image.meta.inventory.main[1]
+		local build_item = ""
+		if node_image.meta.inventory.main then
+			build_item = node_image.meta.inventory.main[1]
+		end
 		if build_item ~= "" then
 			local build_item_def = minetest.registered_nodes[ItemStack(build_item):get_name()]
 			if build_item_def ~= nil then
@@ -462,4 +465,4 @@ function DigtronLayout.deserialize(layout_string)
 	self.old_pos_pointset = Pointset.create() -- needed by the write_layout method, leave empty
 
 	return self
-end
\ No newline at end of file
+end