diff --git a/servers/slapd/back-mdb/config.c b/servers/slapd/back-mdb/config.c
index aab0b51e65..e041db18f0 100644
--- a/servers/slapd/back-mdb/config.c
+++ b/servers/slapd/back-mdb/config.c
@@ -717,7 +717,7 @@ mdb_cf_gen( ConfigArgs *c )
 		if ( c->value_int )
 			mdb->mi_dbenv_flags |= MDB_NOSYNC;
 		else
-			mdb->mi_dbenv_flags ^= MDB_NOSYNC;
+			mdb->mi_dbenv_flags &= ~MDB_NOSYNC;
 		if ( mdb->mi_flags & MDB_IS_OPEN ) {
 			mdb_env_set_flags( mdb->mi_dbenv, MDB_NOSYNC,
 				c->value_int );