diff --git a/mods/CORE/mcl_util/init.lua b/mods/CORE/mcl_util/init.lua
index 58285039a..0972e5019 100644
--- a/mods/CORE/mcl_util/init.lua
+++ b/mods/CORE/mcl_util/init.lua
@@ -23,6 +23,7 @@ function table.update_nil(t, ...)
 end
 
 function mcl_util.file_exists(name)
+	if type(name) ~= "string" then return end
 	local f = io.open(name)
 	if not f then
 		return false
diff --git a/mods/MAPGEN/mcl_structures/api.lua b/mods/MAPGEN/mcl_structures/api.lua
index 719beebd8..6a7fc2c39 100644
--- a/mods/MAPGEN/mcl_structures/api.lua
+++ b/mods/MAPGEN/mcl_structures/api.lua
@@ -32,8 +32,8 @@ local function ecb_place(blockpos, action, calls_remaining, param)
 end
 
 function mcl_structures.place_schematic(pos, schematic, rotation, replacements, force_placement, flags, after_placement_callback, pr, callback_param)
-	if not mcl_util.file_exists(schematic) then
-		minetest.log("warning","[mcl_structures] schematic file "..schematic.." does not exist.")
+	if type(schematic) ~= "table" and not mcl_util.file_exists(schematic) then
+		minetest.log("warning","[mcl_structures] schematic file "..tostring(schematic).." does not exist.")
 		return end
 	local s = loadstring(minetest.serialize_schematic(schematic, "lua", {lua_use_comments = false, lua_num_indent_spaces = 0}) .. " return schematic")()
 	if s and s.size then