--- thunar-1.4.0.orig/thunar/thunar-gio-extensions.c
+++ thunar-1.4.0/thunar/thunar-gio-extensions.c
@@ -249,6 +249,11 @@ thunar_g_vfs_is_uri_scheme_supported (co
   gvfs = g_vfs_get_default ();
   supported_schemes = g_vfs_get_supported_uri_schemes (gvfs);
 
+  if (!supported_schemes)
+    {
+      return FALSE;
+    }
+
   for (n = 0; !supported && supported_schemes[n] != NULL; ++n) 
     if (g_strcmp0 (supported_schemes[n], scheme) == 0)
       supported = TRUE;