diff --git a/src/core/ddsc/src/dds_init.c b/src/core/ddsc/src/dds_init.c
index 639f156..90f0d64 100644
--- a/src/core/ddsc/src/dds_init.c
+++ b/src/core/ddsc/src/dds_init.c
@@ -217,7 +217,6 @@ extern void dds_fini (void)
 
 static int dds__init_plugin (void)
 {
-  os_mutexInit (&gv.attach_lock);
   dds_iid_init ();
   if (dds_global.m_dur_init) (dds_global.m_dur_init) ();
   return 0;
@@ -225,7 +224,6 @@ static int dds__init_plugin (void)
 
 static void dds__fini_plugin (void)
 {
-  os_mutexDestroy (&gv.attach_lock);
   if (dds_global.m_dur_fini) (dds_global.m_dur_fini) ();
   dds_iid_fini ();
 }
diff --git a/src/core/ddsi/include/ddsi/q_globals.h b/src/core/ddsi/include/ddsi/q_globals.h
index 3a58790..733f697 100644
--- a/src/core/ddsi/include/ddsi/q_globals.h
+++ b/src/core/ddsi/include/ddsi/q_globals.h
@@ -190,11 +190,6 @@ struct q_globals {
 
   os_mutex lock;
 
-  /* guarantees serialisation of attach/detach operations on waitsets
-     -- a single global lock is a bit coarse, but these operations are
-     rare and at initialisation time anyway */
-  os_mutex attach_lock;
-
   /* Receive thread. (We can only has one for now, cos of the signal
      trigger socket.) Receive buffer pool is per receive thread,
      practical considerations led to it being a global variable