diff --git a/src/errors.h b/src/errors.h
index bbfe6bb..12f187a 100644
--- a/src/errors.h
+++ b/src/errors.h
@@ -2894,8 +2894,7 @@
 #endif
 EXTERN char e_cmd_mapping_must_end_with_cr_before_second_cmd[]
 	INIT(= N_("E1136: <Cmd> mapping must end with <CR> before second <Cmd>"));
-EXTERN char e_cmd_mapping_must_not_include_str_key[]
-	INIT(= N_("E1137: <Cmd> mapping must not include %s key"));
+// E1137 unused
 #ifdef FEAT_EVAL
 EXTERN char e_using_bool_as_number[]
 	INIT(= N_("E1138: Using a Bool as a Number"));