diff --git a/OPTYap/opt.config.h b/OPTYap/opt.config.h
index d7b16baf1..7361cbf6d 100644
--- a/OPTYap/opt.config.h
+++ b/OPTYap/opt.config.h
@@ -52,7 +52,7 @@
 /* ------------------------------------------------ **
 **      support trie compact pairs? (optional)      **
 ** ------------------------------------------------ */
-#define TRIE_COMPACT_PAIRS 1
+/* #define TRIE_COMPACT_PAIRS 1 */
 
 /* --------------------------------------------------- **
 **      support deterministic tabling? (optional)      **