diff --git a/openless-all/app/src-tauri/src/lib.rs b/openless-all/app/src-tauri/src/lib.rs
index f2e28569..0b449b71 100644
--- a/openless-all/app/src-tauri/src/lib.rs
+++ b/openless-all/app/src-tauri/src/lib.rs
@@ -288,6 +288,7 @@ macro_rules! app_invoke_handler_desktop {
             commands::sherpa_onnx_asr_reveal_model_dir,
             commands::export_error_log,
             restart_app,
+            log_client_error,
             set_windows_caption_theme,
         ]
     };
@@ -378,6 +379,7 @@ macro_rules! app_invoke_handler_mobile {
             $crate::commands::app_check_update_with_channel,
             $crate::commands::app_download_and_install_android_update,
             $crate::restart_app,
+            $crate::log_client_error,
         ]
     };
 }
@@ -1140,6 +1142,26 @@ fn restart_app(app: AppHandle) {
     app.restart();
 }
 
+/// 把前端的关键错误（如自动更新 install 失败）转发到 Rust 文件日志（openless.log）。
+/// webview 的 console.error 不会进 openless.log，单独留一个 IPC，便于用户「导出日志」
+/// 后我们拿到自动更新失败的真实原因。
+#[tauri::command]
+fn log_client_error(message: String) {
+    // message 由前端 webview 可控，可能很长或含换行（伪造日志行）。先把换行折成空格、
+    // 再按 UTF-8 字符边界截断，避免单条日志过大或污染日志格式。
+    const MAX_LEN: usize = 2048;
+    let mut sanitized = message.replace(['\n', '\r'], " ");
+    if sanitized.len() > MAX_LEN {
+        let mut end = MAX_LEN;
+        while !sanitized.is_char_boundary(end) {
+            end -= 1;
+        }
+        sanitized.truncate(end);
+        sanitized.push_str("…(truncated)");
+    }
+    log::error!("[client] {sanitized}");
+}
+
 #[cfg(target_os = "macos")]
 fn reset_tcc_for_beta_restart() {
     if !is_beta_build() {
diff --git a/openless-all/app/src/components/AutoUpdate.tsx b/openless-all/app/src/components/AutoUpdate.tsx
index ac9a008e..ec321d03 100644
--- a/openless-all/app/src/components/AutoUpdate.tsx
+++ b/openless-all/app/src/components/AutoUpdate.tsx
@@ -15,6 +15,8 @@ import {
   appDownloadAndInstallAndroidUpdate,
   isAndroid,
   isTauri,
+  logClientError,
+  openExternal,
   restartApp,
   type AppUpdateMetadata,
   type UpdateChannel,
@@ -23,6 +25,9 @@ import { Btn } from '../pages/_atoms';
 
 const UPDATE_CHECK_TIMEOUT_MS = 15_000;
 
+// 自动更新失败时的手动下载兜底：直达 GitHub Releases（与「关于」页 RELEASE_NOTES_URL 一致）。
+const RELEASE_DOWNLOAD_URL = 'https://github.com/appergb/openless/releases';
+
 export type UpdateStatus =
   | 'idle'
   | 'checking'
@@ -31,7 +36,11 @@ export type UpdateStatus =
   | 'downloading'
   | 'installing'
   | 'downloaded'
-  | 'error';
+  | 'error'
+  // installError：下载/安装这一步失败（区别于 'error' 的「检查失败」）。
+  // 检查失败沿用 'error'，在 CheckUpdateButton 里只做按钮内轻提示、不弹框，
+  // 后台自动检查失败也不弹框；只有 installError 才让弹框留在原地显示错误 + 手动下载兜底。
+  | 'installError';
 
 export interface UseAutoUpdate {
   status: UpdateStatus;
@@ -162,6 +171,7 @@ export function useAutoUpdate(): UseAutoUpdate {
     } catch (error) {
       console.error('[updater] failed to check update', error);
       const msg = error instanceof Error ? error.message : String(error);
+      void logClientError(`[updater] check failed: ${msg}`);
       setErrorMessage(msg);
       setStatus('error');
     }
@@ -180,8 +190,9 @@ export function useAutoUpdate(): UseAutoUpdate {
       } catch (error) {
         console.error('[updater] failed to install android update', error);
         const msg = error instanceof Error ? error.message : String(error);
+        void logClientError(`[updater] android install failed (v${payload.version}): ${msg}`);
         setErrorMessage(msg);
-        setStatus('error');
+        setStatus('installError');
       }
       return;
     }
@@ -208,9 +219,10 @@ export function useAutoUpdate(): UseAutoUpdate {
     } catch (error) {
       console.error('[updater] failed to install update', error);
       const msg = error instanceof Error ? error.message : String(error);
+      void logClientError(`[updater] install failed (v${update.version}): ${msg}`);
       setErrorMessage(msg);
       await closeUpdate();
-      setStatus('error');
+      setStatus('installError');
     }
   };
 
@@ -237,8 +249,8 @@ export function useAutoUpdate(): UseAutoUpdate {
   };
 }
 
-export function isDialogStatus(status: UpdateStatus): status is 'available' | 'downloading' | 'installing' | 'downloaded' {
-  return status === 'available' || status === 'downloading' || status === 'installing' || status === 'downloaded';
+export function isDialogStatus(status: UpdateStatus): status is 'available' | 'downloading' | 'installing' | 'downloaded' | 'installError' {
+  return status === 'available' || status === 'downloading' || status === 'installing' || status === 'downloaded' || status === 'installError';
 }
 
 export function UpdateDialog({
@@ -247,29 +259,34 @@ export function UpdateDialog({
   progress,
   downloaded,
   contentLength,
+  errorMessage,
   onInstall,
   onClose,
 }: {
-  status: 'available' | 'downloading' | 'installing' | 'downloaded';
+  status: 'available' | 'downloading' | 'installing' | 'downloaded' | 'installError';
   version: string;
   progress: number | null;
   downloaded: number;
   contentLength: number | null;
+  errorMessage?: string | null;
   onInstall: () => void;
   onClose: () => void;
 }) {
   const { t } = useTranslation();
   const downloading = status === 'downloading';
   const installing = status === 'installing';
+  const installError = status === 'installError';
   const androidInstalled = isAndroid() && status === 'downloaded';
   return (
     <div style={{ position: 'fixed', inset: 0, background: 'rgba(0,0,0,0.18)', display: 'grid', placeItems: 'center', zIndex: 40 }}>
       <div style={{ width: 360, borderRadius: 16, background: 'var(--ol-surface)', border: '0.5px solid var(--ol-line-strong)', boxShadow: '0 18px 42px rgba(0,0,0,0.18)', padding: 18 }}>
         <div style={{ fontSize: 15, fontWeight: 650, marginBottom: 8 }}>{t(`settings.about.updateDialog.${status}.title`)}</div>
-        <div style={{ fontSize: 12, color: 'var(--ol-ink-3)', lineHeight: 1.6, marginBottom: 14 }}>
+        <div style={{ fontSize: 12, color: 'var(--ol-ink-3)', lineHeight: 1.6, marginBottom: 14, whiteSpace: 'pre-wrap', wordBreak: 'break-word' }}>
           {androidInstalled
             ? t('settings.about.updateDialog.androidInstalled.desc', { version, defaultValue: '系统安装器已打开，请按提示完成安装。安装后重新打开 OpenLess 即可使用 {{version}}。' })
-            : t(`settings.about.updateDialog.${status}.desc`, { version })}
+            : installError
+              ? t('settings.about.updateDialog.installError.desc', { error: errorMessage || t('settings.about.updateError') })
+              : t(`settings.about.updateDialog.${status}.desc`, { version })}
         </div>
         {(downloading || installing || status === 'downloaded') && (
           <div style={{ marginBottom: 14 }}>
@@ -291,6 +308,8 @@ export function UpdateDialog({
           {(downloading || installing) && <Btn size="sm" disabled>{installing ? t('settings.about.updateDialog.installingLabel') : t('settings.about.updateDialog.downloadingLabel')}</Btn>}
           {status === 'downloaded' && <Btn size="sm" onClick={onClose}>{t('settings.about.updateDialog.later')}</Btn>}
           {status === 'downloaded' && !androidInstalled && <Btn variant="blue" size="sm" onClick={restartApp}>{t('settings.about.updateDialog.restartNow')}</Btn>}
+          {installError && <Btn size="sm" onClick={onClose}>{t('common.cancel')}</Btn>}
+          {installError && <Btn variant="blue" size="sm" onClick={() => void openExternal(RELEASE_DOWNLOAD_URL)}>{t('settings.about.updateDialog.manualDownload')}</Btn>}
         </div>
       </div>
     </div>
diff --git a/openless-all/app/src/components/AutoUpdateGate.tsx b/openless-all/app/src/components/AutoUpdateGate.tsx
index 7ff1b6b7..a5a3dbc2 100644
--- a/openless-all/app/src/components/AutoUpdateGate.tsx
+++ b/openless-all/app/src/components/AutoUpdateGate.tsx
@@ -60,6 +60,7 @@ export function AutoUpdateGate() {
       progress={u.progress}
       downloaded={u.downloaded}
       contentLength={u.contentLength}
+      errorMessage={u.errorMessage}
       onInstall={u.installUpdate}
       onClose={u.dismissDialog}
     />
diff --git a/openless-all/app/src/i18n/en.ts b/openless-all/app/src/i18n/en.ts
index fcf71ca3..0e7f57b2 100644
--- a/openless-all/app/src/i18n/en.ts
+++ b/openless-all/app/src/i18n/en.ts
@@ -1041,6 +1041,11 @@ export const en: typeof zhCN = {
         restartNow: 'Restart now',
         progress: '{{progress}}% · {{downloaded}} / {{total}}',
         progressUnknown: '{{downloaded}} downloaded',
+        installError: {
+          title: 'Update failed',
+          desc: "The automatic update couldn't finish: {{error}}. You can download and install the latest version manually.",
+        },
+        manualDownload: 'Download manually',
       },
     },
   },
diff --git a/openless-all/app/src/i18n/ja.ts b/openless-all/app/src/i18n/ja.ts
index 257bfb7f..98cc54c8 100644
--- a/openless-all/app/src/i18n/ja.ts
+++ b/openless-all/app/src/i18n/ja.ts
@@ -1009,6 +1009,11 @@ export const ja: typeof zhCN = {
         restartNow: '今すぐ再起動',
         progress: '{{progress}}% · {{downloaded}} / {{total}}',
         progressUnknown: 'ダウンロード済み {{downloaded}}',
+        installError: {
+          title: '更新に失敗しました',
+          desc: '自動更新を完了できませんでした：{{error}}。ダウンロードページから手動で最新版を入手できます。',
+        },
+        manualDownload: '手動でダウンロード',
       },
     },
   },
diff --git a/openless-all/app/src/i18n/ko.ts b/openless-all/app/src/i18n/ko.ts
index 395f92e1..0ec2d055 100644
--- a/openless-all/app/src/i18n/ko.ts
+++ b/openless-all/app/src/i18n/ko.ts
@@ -1009,6 +1009,11 @@ export const ko: typeof zhCN = {
         restartNow: '지금 재시작',
         progress: '{{progress}}% · {{downloaded}} / {{total}}',
         progressUnknown: '다운로드됨 {{downloaded}}',
+        installError: {
+          title: '업데이트 실패',
+          desc: '자동 업데이트를 완료하지 못했습니다: {{error}}. 다운로드 페이지에서 최신 버전을 직접 받아 설치할 수 있습니다.',
+        },
+        manualDownload: '수동 다운로드',
       },
     },
   },
diff --git a/openless-all/app/src/i18n/zh-CN.ts b/openless-all/app/src/i18n/zh-CN.ts
index 3147b416..890004e4 100644
--- a/openless-all/app/src/i18n/zh-CN.ts
+++ b/openless-all/app/src/i18n/zh-CN.ts
@@ -1039,6 +1039,11 @@ export const zhCN = {
         restartNow: '现在重启',
         progress: '{{progress}}% · {{downloaded}} / {{total}}',
         progressUnknown: '已下载 {{downloaded}}',
+        installError: {
+          title: '更新失败',
+          desc: '自动更新没能完成：{{error}}。你可以前往下载页手动下载安装最新版本。',
+        },
+        manualDownload: '手动下载',
       },
     },
   },
diff --git a/openless-all/app/src/i18n/zh-TW.ts b/openless-all/app/src/i18n/zh-TW.ts
index 2fe58825..25324a6e 100644
--- a/openless-all/app/src/i18n/zh-TW.ts
+++ b/openless-all/app/src/i18n/zh-TW.ts
@@ -1007,6 +1007,11 @@ export const zhTW: typeof zhCN = {
         restartNow: '現在重啓',
         progress: '{{progress}}% · {{downloaded}} / {{total}}',
         progressUnknown: '已下載 {{downloaded}}',
+        installError: {
+          title: '更新失敗',
+          desc: '自動更新未能完成：{{error}}。你可以前往下載頁手動下載安裝最新版本。',
+        },
+        manualDownload: '手動下載',
       },
     },
   },
diff --git a/openless-all/app/src/lib/ipc/index.ts b/openless-all/app/src/lib/ipc/index.ts
index b0afaf42..f83f7ef8 100644
--- a/openless-all/app/src/lib/ipc/index.ts
+++ b/openless-all/app/src/lib/ipc/index.ts
@@ -195,4 +195,4 @@ export {
 } from "./marketplace-cache"
 
 // utils
-export { openExternal, exportErrorLog } from "./utils"
+export { openExternal, exportErrorLog, logClientError } from "./utils"
diff --git a/openless-all/app/src/lib/ipc/utils.ts b/openless-all/app/src/lib/ipc/utils.ts
index 3f2ef98f..233d1733 100644
--- a/openless-all/app/src/lib/ipc/utils.ts
+++ b/openless-all/app/src/lib/ipc/utils.ts
@@ -47,3 +47,16 @@ export async function exportErrorLog(
     )
     return target
 }
+
+/**
+ * 把前端关键错误（如自动更新 install 失败）转发到 Rust 文件日志（openless.log）。
+ * webview 的 console.error 不会落进 openless.log，单独走 IPC，便于用户「导出日志」
+ * 后我们拿到失败的真实原因。永不抛错——日志失败不应再影响调用方的错误处理。
+ */
+export async function logClientError(message: string): Promise<void> {
+    try {
+        await invokeOrMock<void>("log_client_error", { message }, () => undefined)
+    } catch (error) {
+        console.warn("[log-client-error] failed to forward error to app log", error)
+    }
+}
diff --git a/openless-all/app/src/pages/settings/CheckUpdateButton.tsx b/openless-all/app/src/pages/settings/CheckUpdateButton.tsx
index 19106fd2..73cb3132 100644
--- a/openless-all/app/src/pages/settings/CheckUpdateButton.tsx
+++ b/openless-all/app/src/pages/settings/CheckUpdateButton.tsx
@@ -62,6 +62,7 @@ export function CheckUpdateButton({ channel }: { channel: UpdateChannel }) {
           progress={updater.progress}
           downloaded={updater.downloaded}
           contentLength={updater.contentLength}
+          errorMessage={updater.errorMessage}
           onInstall={() => void updater.installUpdate()}
           onClose={() => void updater.dismissDialog()}
         />