diff --git a/modules/htable/ht_api.c b/modules/htable/ht_api.c
index 690f9c75e4c..fb0b11760cc 100644
--- a/modules/htable/ht_api.c
+++ b/modules/htable/ht_api.c
@@ -672,7 +672,10 @@ ht_cell_t* ht_cell_value_add(ht_t *ht, str *name, int val, int mode,
 	}
 	/* add val if htable has an integer init value */
 	if(ht->flags!=PV_VAL_INT)
+	{
+		if(mode) ht_slot_unlock(ht, idx);
 		return NULL;
+	}
 	isval.n = ht->initval.n + val;
 	it = ht_cell_new(name, 0, &isval, hid);
 	if(it == NULL)