diff --git a/configure.ac b/configure.ac
index f7a009655..202b3e6e5 100644
--- a/configure.ac
+++ b/configure.ac
@@ -186,7 +186,7 @@ AC_ARG_ENABLE(fortress,
 
 if test "$ENABLED_FORTRESS" = "yes"
 then
-    AM_CFLAGS="$AM_CFLAGS -DFORTRESS -DBIG_SESSION_CACHE -DOPENSSL_EXTRA -DCYASSL_DES_ECB -DCYASSL_AES_COUNTER -DCYASSL_AES_DIRECT -DCYASSL_DER_LOAD"
+    AM_CFLAGS="$AM_CFLAGS -DFORTRESS -DOPENSSL_EXTRA -DCYASSL_DES_ECB -DCYASSL_AES_COUNTER -DCYASSL_AES_DIRECT -DCYASSL_DER_LOAD"
 fi