modified   libgnucash/backend/xml/gnc-xml-helper.cpp
@@ -31,9 +31,10 @@ checked_char_cast (gchar* val)
     const int length = -1; /* Assumes val is null-terminated */
     gchar* end;
     if (val == NULL) return NULL;
-    /* Replace any invalid UTF-8 characters with a sequence of '?' */
-    while (!g_utf8_validate (val, length, (const gchar**) (&end)))
-        *end = '?';
+    /* Replace any invalid UTF-8 characters with a sequence of 'U+FFFD' */
+
+    g_utf8_make_valid (val, -1);
+
     /* Replace any invalid (for XML) control characters (everything < 0x20
      * except \n, \t, and \r) with '?'. Technically we should replace
      * these with a numeric entity, but that will blow up the libxml