diff --git a/src/backends/meta-monitor-manager-dummy.c b/src/backends/meta-monitor-manager-dummy.c
index d817d0dc1..2ee3bf42c 100644
--- a/src/backends/meta-monitor-manager-dummy.c
+++ b/src/backends/meta-monitor-manager-dummy.c
@@ -34,6 +34,7 @@
 #include "backends/meta-monitor.h"
 #include "backends/meta-monitor-config-manager.h"
 #include "backends/meta-output.h"
+#include "meta/main.h"
 #include "meta/util.h"
 
 #define MAX_MONITORS 5
@@ -190,6 +191,12 @@ append_monitor (MetaMonitorManager *manager,
         }
     }
 
+  if (!mode_specs)
+    {
+      g_warning ("Cannot create dummy output: No valid mode specs.");
+      meta_exit (META_EXIT_ERROR);
+    }
+
   for (l = mode_specs; l; l = l->next)
     {
       CrtcModeSpec *spec = l->data;