diff --git a/tools/HPMHookGen/doxygen.conf b/tools/HPMHookGen/doxygen.conf
index e41e9bafe31..2c45193d73e 100644
--- a/tools/HPMHookGen/doxygen.conf
+++ b/tools/HPMHookGen/doxygen.conf
@@ -166,8 +166,6 @@ MAN_EXTENSION          = .3
 MAN_LINKS              = NO
 GENERATE_XML           = YES
 XML_OUTPUT             = xml
-XML_SCHEMA             =
-XML_DTD                =
 XML_PROGRAMLISTING     = NO
 GENERATE_AUTOGEN_DEF   = NO
 GENERATE_PERLMOD       = NO