diff -up simgear-2.6.0/simgear/scene/model/SGText.cxx.checkforn simgear-2.6.0/simgear/scene/model/SGText.cxx
--- simgear-2.6.0/simgear/scene/model/SGText.cxx.checkforn	2012-02-17 17:38:44.563895660 -0500
+++ simgear-2.6.0/simgear/scene/model/SGText.cxx	2012-05-29 20:31:35.347601886 -0400
@@ -65,6 +65,16 @@ void SGText::UpdateCallback::operator()(
   // FIXME:
   // hopefully the users never specifies bad formats here
   // this should better be something more robust
+  // It is never safe for format.c_str to be %n.
+  string unsafe ("%n");
+  size_t found;
+
+  found=format.find(unsafe);
+  if (found!=string::npos) {
+     SG_LOG(SG_GENERAL, SG_ALERT, "format type contained %n, but this is unsafe, reverting to %s");
+     format = "%s";
+  }
+
   char buf[256];
   if( numeric ) {
     double d = property->getDoubleValue() * scale + offset;