diff --git a/cache/run_redis.sh b/cache/run_redis.sh
index 50a49c74..8daf6d8b 100755
--- a/cache/run_redis.sh
+++ b/cache/run_redis.sh
@@ -8,5 +8,6 @@ if [ -f  ../../valkey/src/valkey-server ]; then
 elif [ -f ../../redis/src/redis-server ]; then
     ../../redis/src/redis-server ./cache.conf
 else
+    echo "Warning: using system redis-server. Valkey-server or redis-server from source is recommended." >&2
     /usr/bin/redis-server ./cache.conf
 fi
diff --git a/indexing/run_redis.sh b/indexing/run_redis.sh
index 46c4a00a..d6924a0f 100755
--- a/indexing/run_redis.sh
+++ b/indexing/run_redis.sh
@@ -8,6 +8,6 @@ if [ -f  ../../valkey/src/valkey-server ]; then
 elif [ -f ../../redis/src/redis-server ]; then
     ../../redis/src/redis-server ./indexing.conf
 else
+    echo "Warning: using system redis-server. Valkey-server or redis-server from source is recommended." >&2
     /usr/bin/redis-server ./indexing.conf
-
 fi
diff --git a/website/web/__init__.py b/website/web/__init__.py
index ee26554b..46d75faf 100644
--- a/website/web/__init__.py
+++ b/website/web/__init__.py
@@ -968,8 +968,8 @@ def hashlookup(tree_uuid: str) -> str | WerkzeugResponse | Response:
         for sha1, entries in merged.items():
             entries['nodes'] = {node.name for node in entries['nodes']}
     except Exception:  # error or module not enabled
-        merged = False
-        total_ressources = False
+        merged = []
+        total_ressources = []
     return render_template('hashlookup.html', base_tree_uuid=tree_uuid, merged=merged, total_ressources=total_ressources)