diff --git a/src/lib/mutex.h b/src/lib/mutex.h
index 79424111d..bb01a822a 100644
--- a/src/lib/mutex.h
+++ b/src/lib/mutex.h
@@ -91,7 +91,7 @@ lumiera_mutex_destroy (LumieraMutex self);
  */
 struct lumiera_mutexacquirer_struct
 {
-  volatile LumieraMutex mutex;
+  LumieraMutex mutex;
   RESOURCE_HANDLE (rh);
 };
 typedef struct lumiera_mutexacquirer_struct lumiera_mutexacquirer;