diff --git a/circular_saw.lua b/circular_saw.lua
index 94e680e..894c986 100644
--- a/circular_saw.lua
+++ b/circular_saw.lua
@@ -242,6 +242,7 @@ function circular_saw.allow_metadata_inventory_put(
 		local incost = (incount * 8) + microstack:get_count()
 		local maxcost = (stackmax * 8) + 7
 		local cost = circular_saw:get_cost(inv, stackname)
+		if not cost then return 0 end -- NALC Fix crash if cost == nil
 		if (incost + cost) > maxcost then
 			return math.max((maxcost - incost) / cost, 0)
 		end