diff --git a/ClipCascade_Desktop/src/stomp_ws/stomp_manager.py b/ClipCascade_Desktop/src/stomp_ws/stomp_manager.py
index 48a78c4a..6525e2f8 100644
--- a/ClipCascade_Desktop/src/stomp_ws/stomp_manager.py
+++ b/ClipCascade_Desktop/src/stomp_ws/stomp_manager.py
@@ -25,6 +25,7 @@ def __init__(self, config: Config, is_login_phase=True):
         self.clipboard_manager = ClipboardManager(self.config)
         self.cipher_manager = CipherManager(self.config)
         self.notification_manager = NotificationManager(self.config)
+        self.request_manager = RequestManager(self.config)
         self.sys_tray: TaskbarPanel = None
         self.first_conn_lost = True
         self.is_login_phase = is_login_phase
@@ -32,6 +33,9 @@ def __init__(self, config: Config, is_login_phase=True):
         self.is_connected = False
         self.disconnected = False
         self.is_auto_reconnecting = False
+        # Guards the "session expired" notification so a credential-less client
+        # is told once, not on every 10s reconnect attempt.
+        self.session_expired_notified = False
 
     def set_tray_ref(self, sys_tray: TaskbarPanel):
         """
@@ -52,6 +56,22 @@ def connect(self) -> tuple[bool, str]:
         try:
             if self.is_connected:
                 return True, ""
+            # Honor an explicit user disconnect: an auto-reconnect thread that
+            # was already sleeping when the user disconnected must not wake up
+            # and silently re-login/reconnect behind them. manual_reconnect()
+            # clears this flag before calling, so intentional reconnects still
+            # proceed.
+            if self.disconnected:
+                return False, "Websocket disconnected"
+            # A restarted server drops its in-memory sessions, invalidating the
+            # stored cookie. Refresh the session before (re)connecting so the
+            # handshake is not 302-redirected to the login page — which the
+            # underlying websocket client would follow into an invalid "http"
+            # scheme and never recover from. Skipped during the initial login
+            # phase, where authenticate_and_connect() already owns the login.
+            if not self.is_login_phase and self.config.data.get("cookie"):
+                if not self.request_manager.is_session_valid():
+                    self._try_relogin()
             self.client = Client(
                 self.config.data["websocket_url"],
                 headers={
@@ -76,6 +96,7 @@ def connect(self) -> tuple[bool, str]:
             # logging.info("Websocket connected")
             self.is_connected = True
             self.is_auto_reconnecting = False
+            self.session_expired_notified = False
             if not self.first_conn_lost:
                 self.first_conn_lost = True
                 self.notification_manager.notify(
@@ -91,6 +112,35 @@ def connect(self) -> tuple[bool, str]:
             logging.error(msg)
             return False, msg
 
+    def _try_relogin(self) -> bool:
+        """
+        Recover an expired session before reconnecting.
+
+        When the login password was persisted (Save Password) this silently
+        re-authenticates and refreshes the cookie/CSRF token in place, so the
+        following WebSocket connect uses a live session and syncing resumes with
+        no user action. Without stored credentials it notifies the user once
+        (they must re-login manually) and returns False.
+        """
+        if self.config.data.get("password") and self.config.data.get("username"):
+            success, _msg, cookie = self.request_manager.login()
+            if success and cookie:
+                self.config.data["cookie"] = cookie
+                self.config.data["csrf_token"] = self.request_manager.get_csrf_token()
+                self.config.save()
+                self.session_expired_notified = False
+                logging.info("Session had expired; silently re-logged in")
+                return True
+
+        if not self.session_expired_notified:
+            self.session_expired_notified = True
+            self.notification_manager.notify(
+                title=f"{APP_NAME}: Session Expired 🔒",
+                message="Your session ended (the server may have restarted). "
+                "Please re-login to resume clipboard syncing.",
+            )
+        return False
+
     def _on_close(self):
         self.is_connected = False
         # Auto Reconnect
diff --git a/ClipCascade_Desktop/src/utils/request_manager.py b/ClipCascade_Desktop/src/utils/request_manager.py
index 6918974e..0c139335 100644
--- a/ClipCascade_Desktop/src/utils/request_manager.py
+++ b/ClipCascade_Desktop/src/utils/request_manager.py
@@ -21,6 +21,32 @@ def format_cookie(cookie: dict) -> str:
         """
         return f"JSESSIONID={cookie.get('JSESSIONID', '')};"
 
+    def is_session_valid(self) -> bool:
+        """
+        Probe whether the stored session cookie is still authenticated.
+
+        Every protected endpoint 302-redirects to the login page once the
+        server-side session is gone (e.g. after a server restart drops its
+        in-memory sessions). Redirect following is disabled so that 302 is
+        observable instead of being masked by the 200 login page it points to.
+        Network/other errors return True so the caller falls through to the
+        normal WebSocket retry path instead of forcing an unnecessary re-login.
+        """
+        try:
+            response = requests.get(
+                self.config.data["server_url"] + CSRF_URL,
+                headers={
+                    "Cookie": RequestManager.format_cookie(self.config.data["cookie"])
+                },
+                verify=self._verify(),
+                allow_redirects=False,
+                timeout=WEBSOCKET_TIMEOUT / 1000,
+            )
+            return response.status_code == 200
+        except Exception as e:
+            logging.error(f"Error probing session validity: {e}")
+            return True
+
     def login(self) -> tuple[bool, str, dict]:
         try:
             session = requests.Session()