diff --git a/libs/ardour/auv2_scan.cc b/libs/ardour/auv2_scan.cc
index 6abf66360a..9abfb2c985 100644
--- a/libs/ardour/auv2_scan.cc
+++ b/libs/ardour/auv2_scan.cc
@@ -35,6 +35,8 @@
 #include <Carbon/Carbon.h>
 #endif
 
+#undef nil
+
 #ifdef COREAUDIO105
 #define ArdourComponent Component
 #define ArdourDescription ComponentDescription