diff --git a/homeassistant/components/proxmoxve/sensor.py b/homeassistant/components/proxmoxve/sensor.py
index cb7977745cef..3cd8b3717fa7 100644
--- a/homeassistant/components/proxmoxve/sensor.py
+++ b/homeassistant/components/proxmoxve/sensor.py
@@ -426,7 +426,11 @@ STORAGE_SENSORS: tuple[ProxmoxStorageSensorEntityDescription, ...] = (
     ProxmoxStorageSensorEntityDescription(
         key="storage_used_percentage",
         translation_key="storage_used_percentage",
-        value_fn=lambda data: round(data["used_fraction"] * 100, 1),
+        value_fn=lambda data: (
+            round(value * 100, 1)
+            if (value := data.get("used_fraction")) is not None
+            else None
+        ),
         native_unit_of_measurement=PERCENTAGE,
         entity_category=EntityCategory.DIAGNOSTIC,
         state_class=SensorStateClass.MEASUREMENT,
diff --git a/tests/components/proxmoxve/test_sensor.py b/tests/components/proxmoxve/test_sensor.py
index 72b71685a7ec..f4fc55cb97e5 100644
--- a/tests/components/proxmoxve/test_sensor.py
+++ b/tests/components/proxmoxve/test_sensor.py
@@ -5,13 +5,17 @@ from unittest.mock import MagicMock, patch
 import pytest
 from syrupy.assertion import SnapshotAssertion
 
-from homeassistant.const import Platform
+from homeassistant.const import STATE_UNKNOWN, Platform
 from homeassistant.core import HomeAssistant
 from homeassistant.helpers import entity_registry as er
 
 from . import setup_integration
 
-from tests.common import MockConfigEntry, snapshot_platform
+from tests.common import (
+    MockConfigEntry,
+    async_load_json_array_fixture,
+    snapshot_platform,
+)
 
 
 @pytest.fixture(autouse=True)
@@ -38,3 +42,29 @@ async def test_all_entities(
             snapshot,
             mock_config_entry.entry_id,
         )
+
+
+async def test_storage_missing_used_fraction(
+    hass: HomeAssistant,
+    mock_proxmox_client: MagicMock,
+    mock_config_entry: MockConfigEntry,
+) -> None:
+    """Test storage usage percentage sensor when used_fraction is missing."""
+    storage_data = await async_load_json_array_fixture(
+        hass, "nodes/storage.json", "proxmoxve"
+    )
+    # Remove used_fraction from all storage entries
+    storage_without_fraction = [
+        {key: value for key, value in storage.items() if key != "used_fraction"}
+        for storage in storage_data
+    ]
+    mock_proxmox_client._node_mock.storage.get.return_value = storage_without_fraction
+
+    with patch(
+        "homeassistant.components.proxmoxve.PLATFORMS",
+        [Platform.SENSOR],
+    ):
+        await setup_integration(hass, mock_config_entry)
+
+    state = hass.states.get("sensor.storage_local_storage_usage_percentage")
+    assert state.state == STATE_UNKNOWN