diff --git a/diagnostic/index.html b/diagnostic/index.html
index 8279552..e4d803a 100644
--- a/diagnostic/index.html
+++ b/diagnostic/index.html
@@ -570,8 +570,8 @@
         }
         // Chat-History (nach F5 / Reconnect)
         if (msg.type === 'chat_history') {
+          chatBox.innerHTML = '';
           if (msg.messages && msg.messages.length > 0) {
-            chatBox.innerHTML = '';
             for (const m of msg.messages) {
               const el = document.createElement('div');
               el.className = `chat-msg ${m.type}`;
diff --git a/diagnostic/server.js b/diagnostic/server.js
index b19284e..258532c 100644
--- a/diagnostic/server.js
+++ b/diagnostic/server.js
@@ -35,7 +35,7 @@ const state = {
   rvs: { status: "disconnected", lastError: null },
   proxy: { status: "unknown", lastError: null },
 };
-const SESSION_KEY_FILE = "/tmp/aria-active-session";
+const SESSION_KEY_FILE = "/data/active-session";
 let activeSessionKey = (() => {
   try { return fs.readFileSync(SESSION_KEY_FILE, "utf-8").trim(); } catch { return "main"; }
 })();
diff --git a/docker-compose.yml b/docker-compose.yml
index 2a88847..1e2f645 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -96,6 +96,7 @@ services:
     network_mode: "service:aria"                   # Teilt Netzwerk mit aria-core → localhost:18789
     volumes:
       - /var/run/docker.sock:/var/run/docker.sock:ro
+      - ./aria-data/config/diag-state:/data           # Persistenter State (aktive Session etc.)
     environment:
       - ARIA_AUTH_TOKEN=${ARIA_AUTH_TOKEN:-}
       - PROXY_URL=http://proxy:3456