diff --git a/config/import_tree.go b/config/import_tree.go
index c878116da..0e1c39c08 100644
--- a/config/import_tree.go
+++ b/config/import_tree.go
@@ -38,7 +38,7 @@ func loadTree(root string) (*importTree, error) {
 		f = loadFileLibucl
 	default:
 		return nil, fmt.Errorf(
-			"%s: uknown configuration format. Use '.tf' or '.tf.rb' extension",
+			"%s: unknown configuration format. Use '.tf' extension",
 			root)
 	}