diff --git a/gtk2_ardour/simple_export_dialog.cc b/gtk2_ardour/simple_export_dialog.cc
index ad661446cd..d09d98f76b 100644
--- a/gtk2_ardour/simple_export_dialog.cc
+++ b/gtk2_ardour/simple_export_dialog.cc
@@ -31,6 +31,7 @@
 #include "ardour/export_timespan.h"
 #include "ardour/profile.h"
 #include "ardour/session_directory.h"
+#include "ardour/surround_return.h"
 
 #include "nag.h"
 #include "simple_export_dialog.h"
@@ -159,6 +160,11 @@ SimpleExportDialog::set_session (ARDOUR::Session* s)
 		return;
 	}
 
+	if (_vapor_export && (s->surround_master ()->surround_return ()->total_n_channels () > 128)) {
+		set_error ("Error: ADM/BWN files cannot contain more than 128 channels.");
+		return;
+	}
+
 	/* check range */
 	Location*            srl (s->locations ()->session_range_location ());
 	TimeSelection const& tsel (_editor.get_selection ().time);