diff --git a/docs/web/control-ui.md b/docs/web/control-ui.md
index 49410f6c239..886960ebf8b 100644
--- a/docs/web/control-ui.md
+++ b/docs/web/control-ui.md
@@ -754,7 +754,7 @@ Then point the UI at your Gateway WS URL (e.g. `ws://127.0.0.1:18789`).
 
 ## Blank Control UI page
 
-If the browser loads a blank dashboard and DevTools shows no useful error, an extension or early content script may have prevented the JavaScript module app from evaluating. The static page includes a plain HTML recovery panel that appears when `<openclaw-app>` is not registered after startup.
+If the browser loads a blank dashboard and DevTools shows no useful error, an extension or early content script may have prevented the JavaScript module app from evaluating. The static page includes a plain HTML recovery panel that appears when `<openclaw-app>` does not complete its first render after startup.
 
 Use the panel's **Try again** action after changing the browser environment, or reload manually after these checks:
 
diff --git a/ui/index.html b/ui/index.html
index 131fc162224..50d11f5ce82 100644
--- a/ui/index.html
+++ b/ui/index.html
@@ -313,8 +313,7 @@
     </section>
     <script>
       (function () {
-        var tagName = "openclaw-app";
-        var app = document.querySelector(tagName);
+        var app = document.querySelector("openclaw-app");
         var fallback = document.getElementById("openclaw-mount-fallback");
         if (!app || !fallback) return;
 
@@ -330,6 +329,7 @@
         var recoveryAttempt = 0;
         var recoveryInFlight = false;
         var recoveryNavigation = false;
+        var appStarted = false;
 
         try {
           var initialUrl = new URL(window.location.href);
@@ -340,19 +340,6 @@
           }
         } catch (e) {}
 
-        function appMounted() {
-          try {
-            return Boolean(
-              app.isConnected &&
-              window.customElements &&
-              typeof window.customElements.get === "function" &&
-              window.customElements.get(tagName),
-            );
-          } catch (e) {
-            return false;
-          }
-        }
-
         function hideFallback() {
           fallback.hidden = true;
           document.body.classList.remove("openclaw-mount-fallback-active");
@@ -364,14 +351,14 @@
 
         function scheduleRecovery() {
           window.clearTimeout(recoveryTimer);
-          if (appMounted() || recoveryAttempt >= maxRecoveryAttempts) return;
+          if (appStarted || recoveryAttempt >= maxRecoveryAttempts) return;
           var retryDelay = Math.min(delay, 1000 * Math.pow(2, recoveryAttempt));
           recoveryTimer = window.setTimeout(retryCurrentDocument, retryDelay);
         }
 
         function finishRecoveryAttempt() {
           recoveryInFlight = false;
-          if (appMounted()) return;
+          if (appStarted) return;
           if (recoveryAttempt >= maxRecoveryAttempts) {
             setSummary(
               "The gateway is still unavailable. Try again, then check the troubleshooting guide if the problem persists.",
@@ -386,7 +373,7 @@
 
         function retryCurrentDocument() {
           if (
-            appMounted() ||
+            appStarted ||
             recoveryInFlight ||
             recoveryAttempt >= maxRecoveryAttempts ||
             typeof window.fetch !== "function"
@@ -414,7 +401,7 @@
             })
             .then(function (response) {
               if (!response.ok) throw new Error("gateway unavailable");
-              window.location.replace(documentUrl.href);
+              if (!appStarted) window.location.replace(documentUrl.href);
             })
             .catch(function () {
               finishRecoveryAttempt();
@@ -425,7 +412,7 @@
         }
 
         function showFallback() {
-          if (appMounted()) return;
+          if (appStarted) return;
           retryCurrentDocument();
           fallback.hidden = false;
           document.body.classList.add("openclaw-mount-fallback-active");
@@ -445,16 +432,16 @@
 
         armFallbackTimer();
 
-        if (window.customElements && typeof window.customElements.whenDefined === "function") {
-          window.customElements.whenDefined(tagName).then(
-            function () {
-              window.clearTimeout(timer);
-              window.clearTimeout(recoveryTimer);
-              hideFallback();
-            },
-            function () {},
-          );
-        }
+        window.addEventListener(
+          "openclaw-control-ui-rendered",
+          function () {
+            appStarted = true;
+            window.clearTimeout(timer);
+            window.clearTimeout(recoveryTimer);
+            hideFallback();
+          },
+          { once: true },
+        );
 
         if (retry) {
           retry.addEventListener("click", function () {
diff --git a/ui/src/app/app-root.ts b/ui/src/app/app-root.ts
index 5e079cf1c8b..758893f18e3 100644
--- a/ui/src/app/app-root.ts
+++ b/ui/src/app/app-root.ts
@@ -151,6 +151,12 @@ export class OpenClawApp extends OpenClawLightDomElement {
     super.disconnectedCallback();
   }
 
+  protected override firstUpdated(): void {
+    if (this.runtime) {
+      globalThis.dispatchEvent(new Event("openclaw-control-ui-rendered"));
+    }
+  }
+
   private synchronizeGateway(gateway: ApplicationContext["gateway"]) {
     const sourceChanged = gateway !== this.loginGatewaySource;
     if (sourceChanged) {
diff --git a/ui/src/app/mount-fallback.test.ts b/ui/src/app/mount-fallback.test.ts
index 5f544d92bea..86e71149017 100644
--- a/ui/src/app/mount-fallback.test.ts
+++ b/ui/src/app/mount-fallback.test.ts
@@ -114,9 +114,8 @@ describe("Control UI mount fallback", () => {
     },
   );
 
-  it("shows the static troubleshooting panel when the app element is never registered", async () => {
+  it("shows the static troubleshooting panel when the app never renders", async () => {
     const frameWindow = createIsolatedWindow();
-    expect(frameWindow.customElements.get("openclaw-app")).toBeUndefined();
     installFallbackShell(frameWindow, await readIndexHtmlWithDelay(1));
     await waitForWindowTimeout(frameWindow, 10);
 
@@ -147,20 +146,25 @@ describe("Control UI mount fallback", () => {
     expect(fallback.hidden).toBe(false);
   });
 
-  it("keeps the fallback hidden when the app element registers before the timeout", async () => {
+  it("keeps the fallback visible until the app completes its first render", async () => {
     const frameWindow = createIsolatedWindow();
-    installFallbackShell(frameWindow, await readIndexHtmlWithDelay(25));
+    installFallbackShell(frameWindow, await readIndexHtmlWithDelay(1));
     if (!frameWindow.customElements.get("openclaw-app")) {
       frameWindow.customElements.define("openclaw-app", class extends frameWindow.HTMLElement {});
     }
     await frameWindow.customElements.whenDefined("openclaw-app");
-    await waitForWindowTimeout(frameWindow, 35);
+    await waitForWindowTimeout(frameWindow, 10);
 
     const fallback = requireElementById(
       frameWindow,
       "openclaw-mount-fallback",
       frameWindow.HTMLElement,
     );
+    expect(fallback.hidden).toBe(false);
+    expect([...frameWindow.document.body.classList]).toEqual(["openclaw-mount-fallback-active"]);
+
+    frameWindow.dispatchEvent(new frameWindow.Event("openclaw-control-ui-rendered"));
+
     expect(fallback.hidden).toBe(true);
     expect([...frameWindow.document.body.classList]).toEqual([]);
   });
diff --git a/ui/src/e2e/login-gate.e2e.test.ts b/ui/src/e2e/login-gate.e2e.test.ts
index ebcf22aa52f..e36009f3b22 100644
--- a/ui/src/e2e/login-gate.e2e.test.ts
+++ b/ui/src/e2e/login-gate.e2e.test.ts
@@ -322,6 +322,45 @@ suite.define(() => {
     }
   });
 
+  it("retires the static startup fallback after rendering auth-required guidance", async () => {
+    const context = await suite.browser.newContext({ viewport: { height: 900, width: 1280 } });
+    const page = await context.newPage();
+    await page.addInitScript(() => {
+      window.addEventListener("openclaw-control-ui-rendered", () => {
+        const key = "openclaw.control-ui-e2e.render-count";
+        const count = Number.parseInt(sessionStorage.getItem(key) ?? "0", 10);
+        sessionStorage.setItem(key, String(count + 1));
+      });
+    });
+    await page.clock.install();
+    const gateway = await installMockGateway(page, { deferredMethods: ["connect"] });
+
+    try {
+      await page.goto(suite.server.baseUrl);
+      await gateway.waitForRequest("connect");
+      await gateway.rejectDeferred("connect", {
+        code: "INVALID_REQUEST",
+        message: "token missing",
+        details: { code: ConnectErrorDetailCodes.AUTH_TOKEN_MISSING },
+      });
+
+      const authRequired = page.locator('.login-gate__failure[data-kind="auth-required"]');
+      await authRequired.waitFor({ timeout: 10_000 });
+      await page.clock.runFor(12_001);
+
+      expect(await authRequired.isVisible()).toBe(true);
+      expect(await page.locator("#openclaw-mount-fallback").isHidden()).toBe(true);
+      expect((await page.locator("body").getAttribute("class")) ?? "").not.toContain(
+        "openclaw-mount-fallback-active",
+      );
+      expect(
+        await page.evaluate(() => sessionStorage.getItem("openclaw.control-ui-e2e.render-count")),
+      ).toBe("1");
+    } finally {
+      await closeContext(context);
+    }
+  });
+
   it("keeps mobile controls compact, touchable, and keyboard-friendly", async () => {
     const context = await suite.browser.newContext({
       hasTouch: true,
diff --git a/ui/src/e2e/mount-fallback.e2e.test.ts b/ui/src/e2e/mount-fallback.e2e.test.ts
new file mode 100644
index 00000000000..c7e964a8ae2
--- /dev/null
+++ b/ui/src/e2e/mount-fallback.e2e.test.ts
@@ -0,0 +1,163 @@
+import { readFile } from "node:fs/promises";
+import { createServer } from "node:http";
+import path from "node:path";
+import type { Page } from "playwright";
+import { expect, it } from "vitest";
+import { pauseVirtualClock, type ControlUiE2eServer } from "../test-helpers/control-ui-e2e.ts";
+import { createControlUiE2eSuite } from "./control-ui-e2e-suite.test-support.ts";
+
+const indexHtmlPath = path.resolve(
+  process.cwd(),
+  path.basename(process.cwd()) === "ui" ? "index.html" : "ui/index.html",
+);
+const renderEvent = "openclaw-control-ui-rendered";
+const loadCountKey = "openclaw.control-ui-e2e.mount-fallback-loads";
+const renderCountKey = "openclaw.control-ui-e2e.mount-fallback-renders";
+let syntheticModuleRenders = false;
+
+async function startRegisteredElementFixture(): Promise<ControlUiE2eServer> {
+  const indexHtml = await readFile(indexHtmlPath, "utf8");
+  const server = createServer((request, response) => {
+    const requestUrl = new URL(request.url ?? "/", "http://127.0.0.1");
+    if (requestUrl.pathname === "/src/main.ts") {
+      response.setHeader("content-type", "text/javascript; charset=utf-8");
+      response.end(
+        syntheticModuleRenders
+          ? `customElements.define("openclaw-app", class extends HTMLElement {
+              connectedCallback() {
+                this.textContent = "Application rendered";
+                window.dispatchEvent(new Event(${JSON.stringify(renderEvent)}));
+              }
+            });`
+          : 'customElements.define("openclaw-app", class extends HTMLElement {});',
+      );
+      return;
+    }
+    if (requestUrl.pathname === "/") {
+      response.setHeader("content-type", "text/html; charset=utf-8");
+      response.end(indexHtml);
+      return;
+    }
+    response.statusCode = 404;
+    response.end();
+  });
+  await new Promise<void>((resolve, reject) => {
+    server.once("error", reject);
+    server.listen(0, "127.0.0.1", resolve);
+  });
+  const address = server.address();
+  if (!address || typeof address === "string") {
+    throw new Error("Registered-element fixture did not acquire a loopback port");
+  }
+  return {
+    baseUrl: `http://127.0.0.1:${address.port}/`,
+    close: () =>
+      new Promise<void>((resolve, reject) => {
+        server.close((error) => (error ? reject(error) : resolve()));
+      }),
+  };
+}
+
+async function addLifecycleCounters(page: Page): Promise<void> {
+  await page.addInitScript(
+    ({ loadKey, renderedEvent, renderKey }) => {
+      const loadCount = Number.parseInt(sessionStorage.getItem(loadKey) ?? "0", 10);
+      sessionStorage.setItem(loadKey, String(loadCount + 1));
+      window.addEventListener(renderedEvent, () => {
+        const renderCount = Number.parseInt(sessionStorage.getItem(renderKey) ?? "0", 10);
+        sessionStorage.setItem(renderKey, String(renderCount + 1));
+      });
+    },
+    { loadKey: loadCountKey, renderedEvent: renderEvent, renderKey: renderCountKey },
+  );
+}
+
+const registeredElementSuite = createControlUiE2eSuite({
+  name: "Control UI static mount fallback E2E",
+  startServer: startRegisteredElementFixture,
+  startServerBeforeBrowser: true,
+});
+
+registeredElementSuite.define(() => {
+  it("shows the fallback when registration never produces an application render", async () => {
+    syntheticModuleRenders = false;
+    await registeredElementSuite.withPage(
+      { serviceWorkers: "block", viewport: { height: 900, width: 1280 } },
+      async ({ page }) => {
+        await addLifecycleCounters(page);
+        await page.clock.install();
+        await pauseVirtualClock(page);
+        await page.goto(registeredElementSuite.server.baseUrl, { waitUntil: "domcontentloaded" });
+        await page.waitForFunction(() => customElements.get("openclaw-app") !== undefined);
+
+        expect(await page.locator("openclaw-app").textContent()).toBe("");
+        expect(
+          await page.evaluate((key) => sessionStorage.getItem(key), renderCountKey),
+        ).toBeNull();
+
+        await page.clock.runFor(12_001);
+        await page.waitForFunction((key) => sessionStorage.getItem(key) === "2", loadCountKey);
+        await page.clock.runFor(12_001);
+
+        await page.getByRole("heading", { name: "Control UI did not start" }).waitFor();
+        expect(await page.getByRole("button", { name: "Try again" }).isVisible()).toBe(true);
+        expect(await page.getByRole("button", { name: "Keep waiting" }).isVisible()).toBe(true);
+        expect(
+          await page.evaluate((key) => sessionStorage.getItem(key), renderCountKey),
+        ).toBeNull();
+
+        syntheticModuleRenders = true;
+        await Promise.all([
+          page.waitForNavigation({ waitUntil: "domcontentloaded" }),
+          page.getByRole("button", { name: "Try again" }).click(),
+        ]);
+        await page.getByText("Application rendered", { exact: true }).waitFor();
+        await page.clock.runFor(12_001);
+
+        expect(await page.locator("#openclaw-mount-fallback").isHidden()).toBe(true);
+        expect(await page.evaluate((key) => sessionStorage.getItem(key), renderCountKey)).toBe("1");
+      },
+    );
+  });
+});
+
+const runtimeFailureSuite = createControlUiE2eSuite({
+  name: "Control UI failed runtime mount E2E",
+  startServerBeforeBrowser: true,
+});
+
+runtimeFailureSuite.define(() => {
+  it("does not complete startup when application runtime creation throws", async () => {
+    await runtimeFailureSuite.withPage(
+      { serviceWorkers: "block", viewport: { height: 900, width: 1280 } },
+      async ({ page }) => {
+        await addLifecycleCounters(page);
+        await page.addInitScript(() => {
+          const browserGetComputedStyle = globalThis.getComputedStyle.bind(globalThis);
+          Object.defineProperty(globalThis, "getComputedStyle", {
+            configurable: true,
+            value: (element: Element, pseudoElement?: string | null) => {
+              if (customElements.get("openclaw-app")) {
+                throw new Error("forced application runtime creation failure");
+              }
+              return browserGetComputedStyle(element, pseudoElement);
+            },
+          });
+        });
+        await page.clock.install();
+        await pauseVirtualClock(page);
+        await page.goto(runtimeFailureSuite.server.baseUrl, { waitUntil: "domcontentloaded" });
+        await page.waitForFunction(() => customElements.get("openclaw-app") !== undefined);
+
+        await page.clock.runFor(12_001);
+        await page.waitForFunction((key) => sessionStorage.getItem(key) === "2", loadCountKey);
+        await page.clock.runFor(12_001);
+
+        await page.getByRole("heading", { name: "Control UI did not start" }).waitFor();
+        expect(
+          await page.evaluate((key) => sessionStorage.getItem(key), renderCountKey),
+        ).toBeNull();
+      },
+    );
+  });
+});