diff --git a/libs/ardour/butler.cc b/libs/ardour/butler.cc
index 6c954e63b4..af3e8097cb 100644
--- a/libs/ardour/butler.cc
+++ b/libs/ardour/butler.cc
@@ -303,7 +303,9 @@ Butler::thread_work ()
 						break;
 					default:
 						error << string_compose (_("Butler read ahead failure on dstream %1"), tr->name ()) << endmsg;
+#ifndef NDEBUG
 						std::cerr << string_compose (_("Butler read ahead failure on dstream %1"), tr->name ()) << std::endl;
+#endif
 						break;
 				}
 			});
@@ -396,7 +398,9 @@ Butler::flush_tracks_to_disk_normal (std::shared_ptr<RouteList const> rl, uint32
 			default:
 				errors++;
 				error << string_compose (_("Butler write-behind failure on dstream %1"), (*i)->name ()) << endmsg;
+#ifndef NDEBUG
 				std::cerr << string_compose (_("Butler write-behind failure on dstream %1"), (*i)->name ()) << std::endl;
+#endif
 				/* don't break - try to flush all streams in case they
 			   are split across disks.
 			*/
diff --git a/libs/ardour/disk_reader.cc b/libs/ardour/disk_reader.cc
index bf040cf8b3..55374b5175 100644
--- a/libs/ardour/disk_reader.cc
+++ b/libs/ardour/disk_reader.cc
@@ -419,7 +419,9 @@ DiskReader::run (BufferSet& bufs, samplepos_t start_sample, samplepos_t end_samp
 				if (available == 0 && !chaninfo->initialized) {
 					disk_buf.silence (disk_samples_to_consume);
 				} else if (disk_samples_to_consume > available) {
+#ifndef NDEBUG // not rt-safe to print here
 					cerr << "underrun for " << _name << " Available samples: " << available << " required: " << disk_samples_to_consume << endl;
+#endif
 					DEBUG_TRACE (DEBUG::Butler, string_compose ("%1 underrun in %2, total space = %3 vs %4\n", DEBUG_THREAD_SELF, name (), available, disk_samples_to_consume));
 					Underrun ();
 					return;
diff --git a/libs/ardour/session_state.cc b/libs/ardour/session_state.cc
index 58a1192175..78ef96c7cb 100644
--- a/libs/ardour/session_state.cc
+++ b/libs/ardour/session_state.cc
@@ -4630,7 +4630,6 @@ Session::config_changed (std::string p, bool ours)
 		}
 	} else if (p == "default-time-domain") {
 		Temporal::TimeDomain td = config.get_default_time_domain ();
-		std::cerr << "Setting time domain\n";
 		set_time_domain (td);
 		Config->set_preferred_time_domain(td);  /* sync the global default time domain to this newly chosen one */
 	}