diff --git a/autocrafter.lua b/autocrafter.lua
index a6d8ad1..b9edd93 100644
--- a/autocrafter.lua
+++ b/autocrafter.lua
@@ -9,7 +9,9 @@ local function make_inventory_cache(invlist)
 end
 
 local function autocraft(inventory, pos)
+	if not inventory then return end
 	local recipe = inventory:get_list("recipe")
+	if not recipe then return end
 	local recipe_last
 	local result
 	local new