diff --git a/connection_manager.cc b/connection_manager.cc
index f0a2c92..5085842 100644
--- a/connection_manager.cc
+++ b/connection_manager.cc
@@ -74,9 +74,12 @@
       }
 
       if (!device_policy) {
-        LOG(INFO) << "Disabling updates over cellular as device policy "
+        // Device policy fails to be loaded (possibly due to guest account). We
+        // do not check the local user setting here, which should be checked by
+        // |OmahaRequestAction| during checking for update.
+        LOG(INFO) << "Allowing updates over cellular as device policy "
                      "fails to be loaded.";
-        return false;
+        return true;
       }
 
       if (device_policy->GetAllowedConnectionTypesForUpdate(&allowed_types)) {
@@ -88,11 +91,14 @@
         }
 
         LOG(INFO) << "Allowing updates over cellular per device policy.";
+        return true;
       }
 
       // If there's no update setting in the device policy, we do not check
       // the local user setting here, which should be checked by
       // |OmahaRequestAction| during checking for update.
+      LOG(INFO) << "Allowing updates over cellular as device policy does "
+                   "not include update setting.";
       return true;
     }
 
diff --git a/connection_manager_unittest.cc b/connection_manager_unittest.cc
index 547539b..0005b2e 100644
--- a/connection_manager_unittest.cc
+++ b/connection_manager_unittest.cc
@@ -334,6 +334,14 @@
                                         ConnectionTethering::kUnknown));
 }
 
+TEST_F(ConnectionManagerTest,
+       AllowUpdatesOverCellularIfPolicyFailsToBeLoaded) {
+  fake_system_state_.set_device_policy(nullptr);
+
+  EXPECT_TRUE(cmut_.IsUpdateAllowedOver(ConnectionType::kCellular,
+                                        ConnectionTethering::kUnknown));
+}
+
 TEST_F(ConnectionManagerTest, StringForConnectionTypeTest) {
   EXPECT_STREQ(shill::kTypeEthernet,
                StringForConnectionType(ConnectionType::kEthernet));
diff --git a/omaha_request_action.cc b/omaha_request_action.cc
index 47f3e37..ee9e920 100644
--- a/omaha_request_action.cc
+++ b/omaha_request_action.cc
@@ -1621,10 +1621,12 @@
     // is set regarding updates over cellular.
     if (!is_allowed)
       *error = ErrorCode::kOmahaUpdateIgnoredPerPolicy;
-  } else if (!IsUpdateAllowedOverCellularByPrefs(response)) {
-    // The user prefereces does not allow updates over cellular.
-    is_allowed = false;
-    *error = ErrorCode::kOmahaUpdateIgnoredOverCellular;
+  } else {
+    // Deivce policy is not set, so user preferences overwrite whether to
+    // allow updates over cellular.
+    is_allowed = IsUpdateAllowedOverCellularByPrefs(response);
+    if (!is_allowed)
+      *error = ErrorCode::kOmahaUpdateIgnoredOverCellular;
   }
 
   LOG(INFO) << "We are connected via "