diff --git a/src/scheduler.c b/src/scheduler.c
index 5b818830e5dafe5ff93303ff32003e9db5f2f235..9170b016160f9ad6e91b9bfb6187bfb0da9e9245 100644
--- a/src/scheduler.c
+++ b/src/scheduler.c
@@ -772,8 +772,8 @@ struct task *scheduler_addtask(struct scheduler *s, enum task_types type,
   const int ind = atomic_inc(&s->tasks_next);
 
   /* Overflow? */
-  if (ind >= s->size) error("Task list overflow. Need to increase "
-                            "Scheduler:tasks_per_cell.");
+  if (ind >= s->size) error("Task list overflow (%d). Need to increase "
+                            "Scheduler:tasks_per_cell.", ind);
 
   /* Get a pointer to the new task. */
   struct task *t = &s->tasks[ind];