diff --git a/homeassistant/components/manual/alarm_control_panel.py b/homeassistant/components/manual/alarm_control_panel.py
index 648368db6d07..d29da80e8514 100644
--- a/homeassistant/components/manual/alarm_control_panel.py
+++ b/homeassistant/components/manual/alarm_control_panel.py
@@ -455,12 +455,15 @@ class ManualAlarm(AlarmControlPanelEntity, RestoreEntity):
         await super().async_added_to_hass()
         if state := await self.async_get_last_state():
             self._state_ts = state.last_updated
-            if next_state := state.attributes.get(ATTR_NEXT_STATE):
-                # If in arming or pending state we record the transition,
-                # not the current state
-                self._state = AlarmControlPanelState(next_state)
-            else:
-                self._state = AlarmControlPanelState(state.state)
+            try:
+                if next_state := state.attributes.get(ATTR_NEXT_STATE):
+                    # If in arming or pending state we record the transition,
+                    # not the current state
+                    self._state = AlarmControlPanelState(next_state)
+                else:
+                    self._state = AlarmControlPanelState(state.state)
+            except ValueError:
+                return
 
             if prev_state := state.attributes.get(ATTR_PREVIOUS_STATE):
                 self._previous_state = prev_state
diff --git a/tests/components/manual/test_alarm_control_panel.py b/tests/components/manual/test_alarm_control_panel.py
index fa9248e8f383..80555219ed21 100644
--- a/tests/components/manual/test_alarm_control_panel.py
+++ b/tests/components/manual/test_alarm_control_panel.py
@@ -1338,6 +1338,33 @@ async def test_restore_state(hass: HomeAssistant, expected_state) -> None:
     assert state.state == expected_state
 
 
+async def test_restore_state_invalid(hass: HomeAssistant) -> None:
+    """Ensure invalid restored state does not crash entity setup."""
+    mock_restore_cache(hass, (State("alarm_control_panel.test", "unknown"),))
+
+    hass.set_state(CoreState.starting)
+    mock_component(hass, "recorder")
+
+    assert await async_setup_component(
+        hass,
+        alarm_control_panel.DOMAIN,
+        {
+            "alarm_control_panel": {
+                "platform": "manual",
+                "name": "test",
+                "arming_time": 0,
+                "trigger_time": 0,
+                "disarm_after_trigger": False,
+            }
+        },
+    )
+    await hass.async_block_till_done()
+
+    state = hass.states.get("alarm_control_panel.test")
+    assert state
+    assert state.state == AlarmControlPanelState.DISARMED
+
+
 @pytest.mark.parametrize(
     "expected_state",
     [