diff --git a/gtk2_ardour/ardour_ui.cc b/gtk2_ardour/ardour_ui.cc
index 03c6beab5b..cd7c24d8a7 100644
--- a/gtk2_ardour/ardour_ui.cc
+++ b/gtk2_ardour/ardour_ui.cc
@@ -1551,6 +1551,8 @@ ARDOUR_UI::update_disk_space()
 			samples /= rec_enabled_streams;
 		}
 
+		livetrax_ff_dropdown->set_sensitive (!rec_enabled_streams);
+
 		format_disk_space_label (samples / (float)fr);
 	}
 
diff --git a/gtk2_ardour/ardour_ui_dependents.cc b/gtk2_ardour/ardour_ui_dependents.cc
index 4bdd2ce8b3..e777c75f22 100644
--- a/gtk2_ardour/ardour_ui_dependents.cc
+++ b/gtk2_ardour/ardour_ui_dependents.cc
@@ -436,6 +436,7 @@ ARDOUR_UI::livetrax_setup_windows ()
 	ev_timecode->add (timecode_format_label);
 
 	livetrax_ff_dropdown = manage (new ArdourDropdown ());
+	set_size_request_to_display_given_text(*livetrax_ff_dropdown, ("24 bit WAV/RF64 +++"), 0, 0);
 	Menu_Helpers::MenuList& items (livetrax_ff_dropdown->items());
 	items.push_back (MenuElem (_("24 bit WAV/RF64"), sigc::bind (sigc::mem_fun (*this, &ARDOUR_UI::livetrax_set_file_format), LiveTraxFileFormat (ARDOUR::FormatInt24, ARDOUR::RF64_WAV))));
 	items.push_back (MenuElem (_("24 bit FLAC"), sigc::bind (sigc::mem_fun (*this, &ARDOUR_UI::livetrax_set_file_format), LiveTraxFileFormat (ARDOUR::FormatInt24, ARDOUR::FLAC))));
@@ -877,6 +878,16 @@ ARDOUR_UI::livetrax_set_file_format (LiveTraxFileFormat const & ff)
 		return;
 	}
 
+	/* bail out if any track is armed */
+	std::shared_ptr<RouteList> rl = _session->get_tracks ();
+	for (RouteList::iterator r = rl->begin(); r != rl->end(); ++r) {
+		std::shared_ptr<Track> t = std::dynamic_pointer_cast<Track> (*r);
+		assert (t);
+		if (t->rec_enable_control()->get_value()) {
+			return;
+		}
+	}
+
 	/* Don't reset write sources on header format change */
 
 	_session->disable_file_format_reset ();