diff --git a/src/xinit.c b/src/xinit.c
index 2f3723c..7a5ab28 100644
--- a/src/xinit.c
+++ b/src/xinit.c
@@ -686,7 +686,7 @@ int source_tcl_file(char *s)
   char tmp[1024];
   if(Tcl_EvalFile(interp, s)==TCL_ERROR) { 
     fprintf(errfp, "Tcl_AppInit() error: can not execute %s, please fix:\n", s);
-    fprintf(errfp, Tcl_GetStringResult(interp));
+    fprintf(errfp, "%s", Tcl_GetStringResult(interp));
     fprintf(errfp, "\n");
     my_snprintf(tmp, S(tmp), "tk_messageBox -icon error -type ok -message \
        {Tcl_AppInit() err 1: can not execute %s, please fix:\n %s}",