diff --git a/libs/ardour/export_profile_manager.cc b/libs/ardour/export_profile_manager.cc
index 65b74103ae..893788809f 100644
--- a/libs/ardour/export_profile_manager.cc
+++ b/libs/ardour/export_profile_manager.cc
@@ -724,6 +724,8 @@ ExportProfileManager::get_warnings ()
 {
 	boost::shared_ptr<Warnings> warnings (new Warnings ());
 
+	assert (!channel_configs.empty ());
+
 	ChannelConfigStatePtr channel_config_state = channel_configs.front();
 	TimespanStatePtr timespan_state = timespans.front();