diff --git a/e2e/boot.spec.ts b/e2e/boot.spec.ts
new file mode 100644
index 000000000..64e400eb3
--- /dev/null
+++ b/e2e/boot.spec.ts
@@ -0,0 +1,26 @@
+import { expect, test } from "@playwright/test";
+
+test("a module evaluation failure replaces the splash with copyable details", async ({ page }) => {
+  await page.route("**/src/main.tsx", (route) =>
+    route.fulfill({ contentType: "text/javascript", body: 'throw new Error("Simulated startup failure");' }),
+  );
+  await page.goto("/");
+  await expect(page.getByRole("heading", { name: "OpenIDEA could not start" })).toBeVisible();
+  await expect(page.locator("#splash")).toHaveCount(0);
+  await expect(page.getByRole("textbox", { name: "Startup error details" })).toHaveValue(/Simulated startup failure/);
+  await expect(page.getByRole("button", { name: "Copy details" })).toBeFocused();
+  await expect(page.getByRole("link", { name: "Report an issue" })).toHaveAttribute("href", /github.com/);
+});
+
+test("an unresolved module gets a startup timeout", async ({ page }) => {
+  await page.clock.install();
+  await page.route("**/src/main.tsx", (route) =>
+    route.fulfill({ contentType: "text/javascript", body: "await new Promise(() => {});" }),
+  );
+  await page.goto("/", { waitUntil: "commit" });
+  await page.locator("#splash").waitFor({ state: "attached" });
+  await page.clock.runFor(30_000);
+  await expect(page.getByRole("textbox", { name: "Startup error details" })).toHaveValue(
+    /Startup did not finish within 30 seconds/,
+  );
+});
diff --git a/package.json b/package.json
index 1fb159a4a..722a52f21 100644
--- a/package.json
+++ b/package.json
@@ -7,7 +7,7 @@
   "type": "module",
   "scripts": {
     "dev": "vite",
-    "build": "tsc --noEmit && vite build",
+    "build": "tsc --noEmit && vite build && node scripts/check-webkit.ts",
     "preview": "vite preview",
     "tauri": "node scripts/tauri.ts",
     "test": "vitest run",
diff --git a/public/boot.js b/public/boot.js
index 6f81c4e8b..81e9f6506 100644
--- a/public/boot.js
+++ b/public/boot.js
@@ -1,4 +1,115 @@
-/* global document, localStorage, window */
+/* global document, localStorage, navigator, window */
+// Keep this independent of the module graph: a dependency can fail before main.tsx runs.
+(() => {
+  const zh = navigator.language.toLowerCase().startsWith("zh");
+  const text = zh
+    ? {
+        title: "OpenIDEA 无法启动",
+        report: "请复制下方详情，并附在 GitHub 问题中。",
+        link: "报告问题",
+        copy: "复制详情",
+        copied: "已复制",
+        manual: "无法复制。请选择下方详情并手动复制。",
+        details: "启动错误详情",
+        timeout: "启动未在 30 秒内完成。",
+      }
+    : {
+        title: "OpenIDEA could not start",
+        report: "Copy the details below and include them in a GitHub issue.",
+        link: "Report an issue",
+        copy: "Copy details",
+        copied: "Copied",
+        manual: "Could not copy. Select the details below and copy them.",
+        details: "Startup error details",
+        timeout: "Startup did not finish within 30 seconds.",
+      };
+  let failed = false;
+  let ready = false;
+  const describe = (reason) => {
+    try {
+      if (typeof reason?.stack === "string") {
+        const message = String(reason);
+        return reason.stack.includes(message) ? reason.stack : `${message}\n${reason.stack}`;
+      }
+      return (typeof reason === "string" ? reason : JSON.stringify(reason)) || String(reason);
+    } catch {
+      return "Unknown startup error";
+    }
+  };
+  const show = (reason) => {
+    if (failed || ready) return;
+    failed = true;
+    window.clearTimeout(timer);
+    document.documentElement.dataset.boot = "failed";
+    const render = () => {
+      const panel = document.createElement("section");
+      panel.id = "boot-error";
+      panel.className = "splash boot-error";
+      panel.setAttribute("role", "alert");
+      const title = document.createElement("h1");
+      title.textContent = text.title;
+      const hint = document.createElement("p");
+      hint.textContent = text.report;
+      const details = document.createElement("textarea");
+      details.readOnly = true;
+      details.setAttribute("aria-label", text.details);
+      details.value = `OpenIDEA startup failure\n${navigator.userAgent}\n\n${describe(reason)}`;
+      const actions = document.createElement("div");
+      actions.className = "boot-error-actions";
+      const copy = document.createElement("button");
+      copy.type = "button";
+      copy.textContent = text.copy;
+      const status = document.createElement("p");
+      status.setAttribute("role", "status");
+      copy.addEventListener("click", async () => {
+        try {
+          await navigator.clipboard.writeText(details.value);
+          status.textContent = text.copied;
+        } catch {
+          details.focus();
+          details.select();
+          status.textContent = text.manual;
+        }
+      });
+      const report = document.createElement("a");
+      report.href = "https://github.com/l0ng-ai/openidea/issues/new?template=bug_report.yml";
+      report.target = "_blank";
+      report.rel = "noreferrer";
+      report.textContent = text.link;
+      actions.append(copy, report);
+      panel.append(title, hint, details, actions, status);
+      document.getElementById("splash")?.remove();
+      document.body.appendChild(panel);
+      copy.focus();
+    };
+    if (document.body) render();
+    else document.addEventListener("DOMContentLoaded", render, { once: true });
+  };
+  const onError = (event) => {
+    const target = event.target;
+    if (target?.tagName === "SCRIPT" || (target?.tagName === "LINK" && target.rel === "modulepreload")) {
+      show(`Could not load startup script: ${target.src || target.href}`);
+    } else if (event.error || event.message) {
+      show(event.error || `${event.message}\n${event.filename || ""}:${event.lineno || 0}:${event.colno || 0}`);
+    }
+  };
+  const onRejection = (event) => show(event.reason);
+  const onBootError = (event) => show(event.detail);
+  const onReady = () => {
+    ready = true;
+    window.clearTimeout(timer);
+    window.removeEventListener("error", onError, true);
+    window.removeEventListener("unhandledrejection", onRejection);
+    window.removeEventListener("openidea:boot-error", onBootError);
+    window.removeEventListener("openidea:boot-ready", onReady);
+  };
+  const timer = window.setTimeout(() => show(text.timeout), 30_000);
+  window.addEventListener("error", onError, true);
+  window.addEventListener("unhandledrejection", onRejection);
+  window.addEventListener("openidea:boot-error", onBootError);
+  window.addEventListener("openidea:boot-ready", onReady);
+})();
+
 // Runs before the app's CSS loads: restores the last theme (theme.ts stores it)
 // so a new window starts in it instead of flashing the light default.
 // An external file because the CSP forbids inline scripts.
diff --git a/public/splash.css b/public/splash.css
index ecb40b616..349fcd0c9 100644
--- a/public/splash.css
+++ b/public/splash.css
@@ -67,10 +67,10 @@ body,
     var(--splash-progress-easing, cubic-bezier(0.1, 0.7, 0.3, 1)) both;
 }
 /* Settings window: a dialog, not a launch. Only the bar, and only if loading takes a while. */
-:root[data-window="settings"] .splash {
+:root[data-window="settings"] .splash:not(.boot-error) {
   animation-delay: 400ms;
 }
-:root[data-window="settings"] .splash > :not(.splash-bar) {
+:root[data-window="settings"] .splash:not(.boot-error) > :not(.splash-bar) {
   display: none;
 }
 @keyframes splash-in {
@@ -92,3 +92,63 @@ body,
     animation: none;
   }
 }
+
+.splash.boot-error {
+  align-items: stretch;
+  justify-content: center;
+  gap: 12px;
+  padding: 32px max(24px, calc((100vw - 560px) / 2));
+  overflow: auto;
+  animation: none;
+  font: var(--fs-ui, 13px) / 1.5 var(--font-ui, system-ui, sans-serif);
+  -webkit-user-select: text;
+  user-select: text;
+}
+.boot-error h1 {
+  margin: 0;
+  color: var(--fg, inherit);
+  font-size: 20px;
+  font-weight: 600;
+}
+.boot-error p {
+  margin: 0;
+}
+.boot-error textarea {
+  box-sizing: border-box;
+  width: 100%;
+  min-height: 140px;
+  height: 180px;
+  padding: 12px;
+  resize: vertical;
+  border: 1px solid var(--border-strong, currentColor);
+  border-radius: var(--radius-control, 4px);
+  background: var(--bg-input, transparent);
+  color: inherit;
+  font: 12px / 1.5 var(--font-mono, monospace);
+}
+.boot-error-actions {
+  display: flex;
+  flex-wrap: wrap;
+  align-items: center;
+  gap: 16px;
+}
+.boot-error button {
+  padding: 6px 12px;
+  border: 1px solid var(--border-strong, currentColor);
+  border-radius: var(--radius-control, 4px);
+  background: var(--bg-elev, transparent);
+  color: inherit;
+  font: inherit;
+  cursor: pointer;
+}
+.boot-error button:hover {
+  background: var(--bg-hover, transparent);
+}
+.boot-error a {
+  color: var(--link, inherit);
+  text-underline-offset: 3px;
+}
+.boot-error :is(button, a, textarea):focus-visible {
+  outline: 2px solid var(--focus-ring, var(--boot-accent, currentColor));
+  outline-offset: 2px;
+}
diff --git a/scripts/check-webkit.test.ts b/scripts/check-webkit.test.ts
new file mode 100644
index 000000000..8c7480f0c
--- /dev/null
+++ b/scripts/check-webkit.test.ts
@@ -0,0 +1,43 @@
+// @vitest-environment node
+import { mkdtempSync, mkdirSync, rmSync, writeFileSync } from "node:fs";
+import { tmpdir } from "node:os";
+import { join } from "node:path";
+import { expect, it } from "vitest";
+import { checkBuild, checkSource } from "./check-webkit.ts";
+
+it.each([
+  "Promise.withResolvers()",
+  "Object.groupBy(items, key)",
+  "Array.fromAsync(items)",
+  "text.toWellFormed()",
+  'new RegExp("[a-z]", "v")',
+  'RegExp("(?<=a)b")',
+  "/[a-z]/v",
+  "/(?<!a)b/",
+  'import data from "./data.json" with { type: "json" }',
+])("rejects %s in the Safari 16 startup graph", (source) => {
+  expect(checkSource(source, true).length).toBeGreaterThan(0);
+});
+
+it("does not mistake regex detection strings or named groups for newer syntax", () => {
+  expect(checkSource('const message = "(?<=a)"; const regex = /(?<name>a)/u;', true)).toEqual([]);
+  expect(checkSource("const regex = /(\\(\\?<=)|(\\(\\?<!)/;", true)).toEqual([]);
+});
+
+it("checks the entry's static imports and all lazy chunks for syntax", () => {
+  const dir = mkdtempSync(join(tmpdir(), "openidea-webkit-"));
+  try {
+    mkdirSync(join(dir, "assets"));
+    writeFileSync(join(dir, "index.html"), '<script type="module" src="/assets/entry.js"></script>');
+    writeFileSync(join(dir, "boot.js"), "");
+    writeFileSync(join(dir, "assets/entry.js"), 'import "./dependency.js"; import("./lazy.js");');
+    writeFileSync(join(dir, "assets/dependency.js"), "Promise.withResolvers();");
+    writeFileSync(join(dir, "assets/lazy.js"), "Object.groupBy(items, key); const re = /[a-z]/v;");
+    expect(checkBuild(dir)).toEqual([
+      "assets/dependency.js: Promise.withResolvers requires newer WebKit",
+      "assets/lazy.js: RegExp v flag requires Safari 17",
+    ]);
+  } finally {
+    rmSync(dir, { recursive: true });
+  }
+});
diff --git a/scripts/check-webkit.ts b/scripts/check-webkit.ts
new file mode 100644
index 000000000..a3f43d7cc
--- /dev/null
+++ b/scripts/check-webkit.ts
@@ -0,0 +1,89 @@
+import { readFileSync, readdirSync } from "node:fs";
+import { dirname, resolve } from "node:path";
+import { pathToFileURL } from "node:url";
+import ts from "typescript";
+
+// macOS 11 can update to Safari 16. Keep this floor in sync with vite.config.ts.
+// Syntax lowering does not replace newer runtime APIs in dependencies.
+const newerStatics = new Set([
+  "Promise.withResolvers",
+  "Object.groupBy",
+  "Map.groupBy",
+  "Array.fromAsync",
+  "Atomics.waitAsync",
+  "CSS.registerProperty",
+  "Uint8Array.fromBase64",
+  "Uint8Array.fromHex",
+]);
+const newerMethods = new Set(["isWellFormed", "toWellFormed"]);
+
+export function checkSource(source: string, startup: boolean): string[] {
+  const tree = ts.createSourceFile("bundle.js", source, ts.ScriptTarget.Latest, true, ts.ScriptKind.JS);
+  const errors = new Set<string>();
+  const checkRegex = (pattern: string, flags: string) => {
+    if (flags.includes("v")) errors.add("RegExp v flag requires Safari 17");
+    if (/\(\?<([=!])/.test(pattern)) errors.add("RegExp lookbehind requires Safari 16.4");
+  };
+  const walk = (node: ts.Node) => {
+    if (ts.isRegularExpressionLiteral(node)) {
+      const end = node.text.lastIndexOf("/");
+      checkRegex(node.text.slice(1, end), node.text.slice(end + 1));
+    }
+    if ((ts.isImportDeclaration(node) || ts.isExportDeclaration(node)) && node.attributes) {
+      errors.add("Import attributes require newer WebKit");
+    }
+    if (startup && ts.isPropertyAccessExpression(node)) {
+      const name = node.getText(tree);
+      if (newerStatics.has(name) || newerMethods.has(node.name.text)) errors.add(`${name} requires newer WebKit`);
+    }
+    if (
+      startup &&
+      (ts.isNewExpression(node) || ts.isCallExpression(node)) &&
+      node.expression.getText(tree) === "RegExp" &&
+      node.arguments?.[0] &&
+      ts.isStringLiteralLike(node.arguments[0])
+    ) {
+      const flags = node.arguments[1];
+      checkRegex(node.arguments[0].text, flags && ts.isStringLiteralLike(flags) ? flags.text : "");
+    }
+    ts.forEachChild(node, walk);
+  };
+  walk(tree);
+  return [...errors];
+}
+
+export function checkBuild(dir: string): string[] {
+  const entry = readFileSync(resolve(dir, "index.html"), "utf8").match(/<script type="module"[^>]*src="([^"]+)"/);
+  if (!entry?.[1]) throw new Error("Production entry script was not found");
+  const startup = new Set<string>();
+  const visit = (file: string) => {
+    if (startup.has(file)) return;
+    startup.add(file);
+    const source = readFileSync(file, "utf8");
+    const tree = ts.createSourceFile(file, source, ts.ScriptTarget.Latest, true, ts.ScriptKind.JS);
+    for (const node of tree.statements) {
+      if (
+        (ts.isImportDeclaration(node) || ts.isExportDeclaration(node)) &&
+        node.moduleSpecifier &&
+        ts.isStringLiteral(node.moduleSpecifier)
+      ) {
+        visit(resolve(dirname(file), node.moduleSpecifier.text));
+      }
+    }
+  };
+  visit(resolve(dir, entry[1].replace(/^\//, "")));
+  startup.add(resolve(dir, "boot.js"));
+  const errors: string[] = [];
+  for (const file of readdirSync(dir, { recursive: true, encoding: "utf8" })) {
+    if (!file.endsWith(".js")) continue;
+    const path = resolve(dir, file);
+    for (const error of checkSource(readFileSync(path, "utf8"), startup.has(path))) errors.push(`${file}: ${error}`);
+  }
+  return errors;
+}
+
+if (process.argv[1] && import.meta.url === pathToFileURL(resolve(process.argv[1])).href) {
+  const errors = checkBuild(resolve("dist"));
+  if (errors.length) throw new Error(`Safari 16 compatibility check failed:\n${errors.join("\n")}`);
+  console.log("Safari 16 startup API and bundle syntax checks passed");
+}
diff --git a/src/main.tsx b/src/main.tsx
index af66b639e..82c427bbf 100644
--- a/src/main.tsx
+++ b/src/main.tsx
@@ -1,4 +1,4 @@
-import React from "react";
+import React, { useEffect } from "react";
 import ReactDOM from "react-dom/client";
 import "./styles/global.css";
 import { Workbench } from "./workbench/Workbench";
@@ -14,7 +14,7 @@ import {
 } from "./features";
 import { auxiliaryWindow } from "./platform/auxWindow";
 import { installRepeatedDoubleClick } from "./platform/doubleClick";
-import { installErrorLogging } from "./platform/errorLog";
+import { installErrorLogging, logError } from "./platform/errorLog";
 import { guessOs } from "./platform/platformInfo";
 import { installReorderedTapClick } from "./platform/reordered-tap-click";
 import { installKeyboardDispatcher } from "./platform/keymap";
@@ -72,19 +72,30 @@ if (aux?.kind === "settings") {
   installKeyboardDispatcher();
 }
 
-ReactDOM.createRoot(document.getElementById("root") as HTMLElement).render(
+function App() {
+  useEffect(() => {
+    hideSplash();
+    // Views split out of the start-up bundle load in the background once the UI is up.
+    if (!aux) return prefetchLazyComponents();
+  }, []);
+  return aux?.kind === "settings" ? (
+    <SettingsWindow />
+  ) : aux?.kind === "comparison" ? (
+    <ComparisonWindow />
+  ) : aux?.kind === "deployment" ? (
+    <DeploymentWindow />
+  ) : (
+    <Workbench />
+  );
+}
+
+ReactDOM.createRoot(document.getElementById("root") as HTMLElement, {
+  onUncaughtError: (error) => {
+    logError("Uncaught render error", error);
+    window.dispatchEvent(new CustomEvent("openidea:boot-error", { detail: error }));
+  },
+}).render(
   <React.StrictMode>
-    {aux?.kind === "settings" ? (
-      <SettingsWindow />
-    ) : aux?.kind === "comparison" ? (
-      <ComparisonWindow />
-    ) : aux?.kind === "deployment" ? (
-      <DeploymentWindow />
-    ) : (
-      <Workbench />
-    )}
+    <App />
   </React.StrictMode>,
 );
-hideSplash();
-// Views split out of the start-up bundle load in the background once the UI is up.
-if (!aux) prefetchLazyComponents();
diff --git a/src/platform/boot.test.ts b/src/platform/boot.test.ts
new file mode 100644
index 000000000..df9bbdb38
--- /dev/null
+++ b/src/platform/boot.test.ts
@@ -0,0 +1,109 @@
+import { readFileSync } from "node:fs";
+import { afterEach, beforeEach, expect, it, vi } from "vitest";
+
+const boot = readFileSync("public/boot.js", "utf8");
+
+beforeEach(() => {
+  vi.useFakeTimers();
+  document.body.innerHTML = '<div id="root"></div><div id="splash"></div>';
+  delete document.documentElement.dataset.boot;
+  new Function(boot)();
+});
+afterEach(() => {
+  window.dispatchEvent(new Event("openidea:boot-ready"));
+  vi.useRealTimers();
+  vi.restoreAllMocks();
+  document.body.innerHTML = "";
+});
+
+it("surfaces module evaluation errors before React is available", () => {
+  window.dispatchEvent(new ErrorEvent("error", { error: new SyntaxError("Invalid regular expression") }));
+  expect(document.getElementById("splash")).toBeNull();
+  expect(document.querySelector('[role="alert"]')?.textContent).toContain("OpenIDEA could not start");
+  expect(document.querySelector("textarea")?.value).toContain("Invalid regular expression");
+  expect(document.querySelector("textarea")?.value).toContain(navigator.userAgent);
+});
+
+it("handles startup rejections and preserves the first failure", () => {
+  const event = new Event("unhandledrejection");
+  Object.defineProperty(event, "reason", { value: { message: "startup rejected" } });
+  window.dispatchEvent(event);
+  window.dispatchEvent(new ErrorEvent("error", { message: "later failure" }));
+  expect(document.querySelector("textarea")?.value).toContain("startup rejected");
+  expect(document.querySelector("textarea")?.value).not.toContain("later failure");
+});
+
+it("handles script load failures but ignores image failures", () => {
+  const image = document.createElement("img");
+  document.body.append(image);
+  image.dispatchEvent(new Event("error"));
+  expect(document.getElementById("splash")).not.toBeNull();
+  const script = document.createElement("script");
+  script.type = "module";
+  script.src = "/assets/entry.js";
+  document.body.append(script);
+  script.dispatchEvent(new Event("error"));
+  expect(document.querySelector("textarea")?.value).toContain("/assets/entry.js");
+});
+
+it("surfaces initial React render failures through the boot error event", () => {
+  window.dispatchEvent(new CustomEvent("openidea:boot-error", { detail: new Error("render failed") }));
+  expect(document.querySelector("textarea")?.value).toContain("render failed");
+});
+
+it("reports an unresolved startup instead of waiting forever", () => {
+  vi.advanceTimersByTime(30_000);
+  expect(document.querySelector("textarea")?.value).toContain("Startup did not finish within 30 seconds.");
+});
+
+it("stops intercepting failures after a successful startup", () => {
+  window.dispatchEvent(new Event("openidea:boot-ready"));
+  window.dispatchEvent(new ErrorEvent("error", { message: "runtime failure" }));
+  vi.advanceTimersByTime(30_000);
+  expect(document.getElementById("boot-error")).toBeNull();
+});
+
+it("copies diagnostics and offers manual copying when clipboard access fails", async () => {
+  const writeText = vi.fn().mockRejectedValue(new Error("denied"));
+  Object.defineProperty(navigator, "clipboard", { configurable: true, value: { writeText } });
+  window.dispatchEvent(new ErrorEvent("error", { message: "<script>unsafe</script>" }));
+  document.querySelector("button")?.click();
+  await vi.waitFor(() => expect(document.querySelector('[role="status"]')?.textContent).toContain("Select"));
+  expect(writeText).toHaveBeenCalledWith(expect.stringContaining("<script>unsafe</script>"));
+  expect(document.querySelector("#boot-error script")).toBeNull();
+  expect(document.activeElement).toBe(document.querySelector("textarea"));
+});
+
+it("uses Chinese boot text without loading the application catalog", () => {
+  window.dispatchEvent(new Event("openidea:boot-ready"));
+  vi.spyOn(navigator, "language", "get").mockReturnValue("zh-CN");
+  new Function(boot)();
+  window.dispatchEvent(new ErrorEvent("error", { message: "failure" }));
+  expect(document.querySelector('[role="alert"]')?.textContent).toContain("OpenIDEA 无法启动");
+});
+
+it("confirms a successful copy", async () => {
+  const writeText = vi.fn().mockResolvedValue(undefined);
+  Object.defineProperty(navigator, "clipboard", { configurable: true, value: { writeText } });
+  window.dispatchEvent(new ErrorEvent("error", { message: "startup failed" }));
+  document.querySelector("button")?.click();
+  await vi.waitFor(() => expect(document.querySelector('[role="status"]')?.textContent).toBe("Copied"));
+  expect(writeText).toHaveBeenCalledWith(expect.stringContaining("startup failed"));
+});
+
+it("defers an early script failure until the document body exists", () => {
+  const body = document.body;
+  body.remove();
+  window.dispatchEvent(new ErrorEvent("error", { message: "early failure" }));
+  document.documentElement.append(body);
+  document.dispatchEvent(new Event("DOMContentLoaded"));
+  expect(document.querySelector("textarea")?.value).toContain("early failure");
+});
+
+it("preserves Safari error messages when its stack only lists locations", () => {
+  const error = new SyntaxError("Unsupported regular expression");
+  error.stack = "global code@tauri://localhost/assets/entry.js:1:20";
+  window.dispatchEvent(new ErrorEvent("error", { error }));
+  expect(document.querySelector("textarea")?.value).toContain("SyntaxError: Unsupported regular expression");
+  expect(document.querySelector("textarea")?.value).toContain(error.stack);
+});
diff --git a/src/platform/locales/text/en.json b/src/platform/locales/text/en.json
index 5a4d0189e..4c228228e 100644
--- a/src/platform/locales/text/en.json
+++ b/src/platform/locales/text/en.json
@@ -1,4 +1,12 @@
 {
+  "OpenIDEA could not start": "OpenIDEA could not start",
+  "Copy the details below and include them in a GitHub issue.": "Copy the details below and include them in a GitHub issue.",
+  "Report an issue": "Report an issue",
+  "Copy details": "Copy details",
+  "Copied": "Copied",
+  "Could not copy. Select the details below and copy them.": "Could not copy. Select the details below and copy them.",
+  "Startup error details": "Startup error details",
+  "Startup did not finish within 30 seconds.": "Startup did not finish within 30 seconds.",
   "this data source does not list databases": "this data source does not list databases",
   "commit or roll back before clearing the selected database": "commit or roll back before clearing the selected database",
   "connect_timeout must be greater than zero": "connect_timeout must be greater than zero",
diff --git a/src/platform/locales/text/zh.json b/src/platform/locales/text/zh.json
index d09ef0908..3c5d4f016 100644
--- a/src/platform/locales/text/zh.json
+++ b/src/platform/locales/text/zh.json
@@ -1,4 +1,11 @@
 {
+  "OpenIDEA could not start": "OpenIDEA 无法启动",
+  "Copy the details below and include them in a GitHub issue.": "请复制下方详情，并附在 GitHub 问题中。",
+  "Report an issue": "报告问题",
+  "Copy details": "复制详情",
+  "Could not copy. Select the details below and copy them.": "无法复制。请选择下方详情并手动复制。",
+  "Startup error details": "启动错误详情",
+  "Startup did not finish within 30 seconds.": "启动未在 30 秒内完成。",
   "this data source does not list databases": "此数据源不支持列出数据库",
   "commit or roll back before clearing the selected database": "清除所选数据库前，请先提交或回滚事务",
   "connect_timeout must be greater than zero": "connect_timeout 必须大于零",
diff --git a/src/platform/locales/textCatalog.test.ts b/src/platform/locales/textCatalog.test.ts
index 7a6571115..c3397e078 100644
--- a/src/platform/locales/textCatalog.test.ts
+++ b/src/platform/locales/textCatalog.test.ts
@@ -70,6 +70,8 @@ const NOTIFY = new Set(["notify"]);
 
 /** Code templates shown as written, and the in-memory backends of plain-browser development. */
 const UNCHECKED_FILES = new Set([
+  // Pre-module failure UI carries its own English/Chinese text when catalogs cannot load.
+  "public/boot.js",
   "src/editor/core/backend.ts",
   "src/features/plugins/backend.ts",
   "src/features/tools/backend.ts",
@@ -485,7 +487,10 @@ function scanTypeScript(): Scan {
   const spliced: Use[] = [];
   const keys: Use[] = [];
   const literals = new Set<string>();
-  const files = walk(`${ROOT}src`, (p) => /\.tsx?$/.test(p) && !isTest(p) && !p.endsWith("/bindings.ts"));
+  const files = [
+    ...walk(`${ROOT}src`, (p) => /\.tsx?$/.test(p) && !isTest(p) && !p.endsWith("/bindings.ts")),
+    `${ROOT}public/boot.js`,
+  ];
   for (const file of files) {
     const path = file.slice(ROOT.length);
     const source = readFileSync(file, "utf8");
diff --git a/src/platform/splash.ts b/src/platform/splash.ts
index 6a5b50fbe..431b22603 100644
--- a/src/platform/splash.ts
+++ b/src/platform/splash.ts
@@ -36,8 +36,13 @@ export function hideSplash(): void {
       requestAnimationFrame(() => {
         setTimeout(
           () => {
+            if (document.documentElement.dataset.boot === "failed") return;
             el.classList.add("splash-out");
-            setTimeout(() => el.remove(), 200);
+            setTimeout(() => {
+              if (document.documentElement.dataset.boot === "failed") return;
+              el.remove();
+              window.dispatchEvent(new Event("openidea:boot-ready"));
+            }, 200);
           },
           completeBar(el) ? FILL_MS : 0,
         );