diff --git a/gtk2_ardour/editor_ops.cc b/gtk2_ardour/editor_ops.cc
index 92d4ed63f5..ee78056b7f 100644
--- a/gtk2_ardour/editor_ops.cc
+++ b/gtk2_ardour/editor_ops.cc
@@ -3389,6 +3389,8 @@ Editor::_freeze_thread (void* arg)
 void*
 Editor::freeze_thread ()
 {
+	/* create per-thread buffers for process() calls */
+	ProcessThread::init ();
 	/* create event pool because we may need to talk to the session */
 	SessionEvent::create_per_thread_pool ("freeze events", 64);
 	/* create per-thread buffers for process() tree to use */