diff --git a/installer/niumasoftware.generated.iss b/installer/niumasoftware.generated.iss
index d0df1be..c8a519f 100644
--- a/installer/niumasoftware.generated.iss
+++ b/installer/niumasoftware.generated.iss
@@ -49,7 +49,7 @@ Name: "{autodesktop}\牛马软件柜"; Filename: "{app}\niumasoftware.exe"; Task
 Filename: "{app}\niumasoftware.exe"; Description: "运行 牛马软件柜"; Flags: nowait postinstall skipifsilent
 
 [UninstallRun]
-Filename: "{sys}\schtasks.exe"; Parameters: "/Delete /TN ""CleanDesktopOrganizer\Update"" /F"; Flags: runhidden
+Filename: "{sys}\schtasks.exe"; Parameters: "/Delete /TN ""\CleanDesktopOrganizer\Update"" /F"; Flags: runhidden
 
 [Code]
 procedure CreateUpdateTask();
@@ -60,7 +60,7 @@ begin
   // 计划任务：以 SYSTEM 运行，按需触发（/SC ONDEMAND）
   // 注意：TR 不带参数，update_helper.exe 会读取 ProgramData 请求文件
   Cmd :=
-    '/Create /F /TN "CleanDesktopOrganizer\Update" ' +
+    '/Create /F /TN "\CleanDesktopOrganizer\Update" ' +
     '/RU "SYSTEM" /RL HIGHEST /SC ONDEMAND ' +
     '/TR "' + ExpandConstant('{app}\update_helper.exe') + '"';
 
diff --git a/installer/niumasoftware.iss b/installer/niumasoftware.iss
index 698bdc4..8a812fb 100644
--- a/installer/niumasoftware.iss
+++ b/installer/niumasoftware.iss
@@ -48,7 +48,7 @@ Name: "{autodesktop}\牛马软件柜"; Filename: "{app}\niumasoftware.exe"; Task
 Filename: "{app}\niumasoftware.exe"; Description: "运行 牛马软件柜"; Flags: nowait postinstall skipifsilent
 
 [UninstallRun]
-Filename: "{sys}\schtasks.exe"; Parameters: "/Delete /TN ""CleanDesktopOrganizer\Update"" /F"; Flags: runhidden
+Filename: "{sys}\schtasks.exe"; Parameters: "/Delete /TN ""\CleanDesktopOrganizer\Update"" /F"; Flags: runhidden
 
 [Code]
 procedure CreateUpdateTask();
@@ -59,7 +59,7 @@ begin
   // 计划任务：以 SYSTEM 运行，按需触发（/SC ONDEMAND）
   // 注意：TR 不带参数，update_helper.exe 会读取 ProgramData 请求文件
   Cmd :=
-    '/Create /F /TN "CleanDesktopOrganizer\Update" ' +
+    '/Create /F /TN "\CleanDesktopOrganizer\Update" ' +
     '/RU "SYSTEM" /RL HIGHEST /SC ONDEMAND ' +
     '/TR "' + ExpandConstant('{app}\update_helper.exe') + '"';
 
diff --git a/ui/updater.py b/ui/updater.py
index 0d46484..5263907 100644
--- a/ui/updater.py
+++ b/ui/updater.py
@@ -8,6 +8,8 @@ import sys
 import subprocess
 import tempfile
 import json
+import ctypes
+import base64
 from PyQt6.QtCore import QThread, pyqtSignal, QObject
 from PyQt6.QtWidgets import QProgressDialog, QMessageBox, QApplication
 import urllib.request
@@ -15,7 +17,8 @@ import urllib.request
 
 UPDATE_CHECK_URL = "https://api.yunzer.cn/api/softwareupgrade/check?code=niumasortware"
 APP_NAME = "CleanDesktopOrganizer"
-UPDATE_TASK_NAME = r"CleanDesktopOrganizer\Update"
+# schtasks 的任务名在不同环境下可能需要/不需要前导 "\"，这里两种都尝试
+UPDATE_TASK_NAMES = [r"\CleanDesktopOrganizer\Update", r"CleanDesktopOrganizer\Update"]
 
 
 def _current_version() -> str:
@@ -107,10 +110,10 @@ def _request_file_path() -> str:
     return os.path.join(d, "update_request.json")
 
 
-def _run_update_task() -> bool:
+def _task_exists(name: str) -> bool:
     try:
         r = subprocess.run(
-            ["schtasks", "/Run", "/TN", UPDATE_TASK_NAME],
+            ["schtasks", "/Query", "/TN", name],
             capture_output=True,
             text=True,
             encoding="utf-8",
@@ -122,6 +125,94 @@ def _run_update_task() -> bool:
         return False
 
 
+def _run_update_task() -> bool:
+    for name in UPDATE_TASK_NAMES:
+        if not _task_exists(name):
+            continue
+        try:
+            r = subprocess.run(
+                ["schtasks", "/Run", "/TN", name],
+                capture_output=True,
+                text=True,
+                encoding="utf-8",
+                errors="replace",
+                creationflags=subprocess.CREATE_NO_WINDOW,
+            )
+            if r.returncode == 0:
+                return True
+        except Exception:
+            continue
+    return False
+
+
+def _run_update_helper_elevated() -> bool:
+    """
+    当计划任务不存在时的兜底：以管理员权限运行 update_helper.exe。
+    这会触发 UAC（无法完全静默），但能保证更新能完成。
+    """
+    if sys.platform != "win32":
+        return False
+    try:
+        helper = os.path.join(os.path.dirname(sys.executable), "update_helper.exe")
+        if not os.path.isfile(helper):
+            return False
+        # ShellExecuteW 返回值 > 32 表示成功启动
+        r = ctypes.windll.shell32.ShellExecuteW(None, "runas", helper, None, None, 0)
+        return int(r) > 32
+    except Exception:
+        return False
+
+
+def _run_elevated_copy_and_restart(src: str, dst: str, pid: int) -> bool:
+    """
+    不依赖 update_helper.exe 的兜底方案：
+    直接用管理员权限启动 PowerShell，等待原进程退出后覆盖 dst 并重启。
+    """
+    if sys.platform != "win32":
+        return False
+    try:
+        ps = rf"""
+$pid_target = {int(pid)}
+$src = '{str(src).replace("'", "''")}'
+$dst = '{str(dst).replace("'", "''")}'
+
+$waited = 0
+while ((Get-Process -Id $pid_target -ErrorAction SilentlyContinue) -and $waited -lt 60) {{
+  Start-Sleep -Milliseconds 500
+  $waited += 0.5
+}}
+
+$ok = $false
+for ($i = 0; $i -lt 20; $i++) {{
+  try {{
+    Copy-Item -Path $src -Destination $dst -Force
+    $ok = $true
+    break
+  }} catch {{
+    Start-Sleep -Milliseconds 800
+  }}
+}}
+
+if ($ok) {{
+  Remove-Item $src -Force -ErrorAction SilentlyContinue
+  Start-Process $dst
+}}
+"""
+        # PowerShell -EncodedCommand 需要 UTF-16LE + base64
+        enc = base64.b64encode(ps.encode("utf-16le")).decode("ascii")
+        r = ctypes.windll.shell32.ShellExecuteW(
+            None,
+            "runas",
+            "powershell",
+            f"-NoProfile -NonInteractive -ExecutionPolicy Bypass -EncodedCommand {enc}",
+            None,
+            0,
+        )
+        return int(r) > 32
+    except Exception:
+        return False
+
+
 def _replace_and_restart(new_exe: str):
     """
     onedir 模式：只替换 exe 本身，dll 等文件不变。
@@ -263,8 +354,34 @@ class Updater(QObject):
                 QApplication.quit()
                 return
 
-            # 兜底：如果计划任务不存在/失败，尝试旧的自替换方式（仅当安装目录可写时有效）
-            _replace_and_restart(path)
+            # 兜底策略 1：计划任务不存在时，提示并可通过 UAC 直接运行 update_helper.exe 完成一次更新
+            if _run_update_helper_elevated():
+                QApplication.quit()
+                return
+
+            # 兜底策略 1.5：如果安装目录里没有 update_helper.exe，则直接用管理员 PowerShell 完成覆盖
+            if _run_elevated_copy_and_restart(path, sys.executable, os.getpid()):
+                QApplication.quit()
+                return
+
+            # 兜底策略 2：如果安装目录可写（非常少见），尝试旧的自替换方式
+            try:
+                can_write = os.access(sys.executable, os.W_OK)
+            except Exception:
+                can_write = False
+            if can_write:
+                _replace_and_restart(path)
+                return
+
+            QMessageBox.critical(
+                self._parent_widget,
+                "更新失败",
+                "已下载更新，但未找到/无法运行更新计划任务（需要管理员权限）。\n\n"
+                "请尝试：\n"
+                "1) 以管理员身份重新安装一次安装包（用于创建更新计划任务）\n"
+                "2) 或在“任务计划程序”检查是否存在任务：CleanDesktopOrganizer\\Update\n"
+                "3) 也可尝试用管理员权限运行 update_helper.exe 完成一次更新",
+            )
             return
 
         _replace_and_restart(path)
diff --git a/update_helper.py b/update_helper.py
index f65f112..2d34d21 100644
--- a/update_helper.py
+++ b/update_helper.py
@@ -18,6 +18,7 @@ import time
 
 APP_NAME = "CleanDesktopOrganizer"
 REQUEST_FILE = "update_request.json"
+LOG_FILE = "update.log"
 
 
 def _programdata_dir() -> str:
@@ -29,6 +30,16 @@ def _request_path() -> str:
     return os.path.join(_programdata_dir(), REQUEST_FILE)
 
 
+def _log(msg: str):
+    try:
+        os.makedirs(_programdata_dir(), exist_ok=True)
+        p = os.path.join(_programdata_dir(), LOG_FILE)
+        with open(p, "a", encoding="utf-8") as f:
+            f.write(msg.rstrip() + "\n")
+    except Exception:
+        pass
+
+
 def _read_request() -> dict:
     p = _request_path()
     with open(p, "r", encoding="utf-8") as f:
@@ -79,6 +90,7 @@ def main() -> int:
     except FileNotFoundError:
         return 0
     except Exception:
+        _log("ERROR: cannot read request file")
         return 2
 
     src = str(req.get("src") or "")
@@ -87,8 +99,11 @@ def main() -> int:
     restart = bool(req.get("restart", True))
 
     if not src or not dst:
+        _log(f"ERROR: bad request src={src!r} dst={dst!r} pid={pid}")
         return 3
 
+    _log(f"START: pid={pid} src={src} dst={dst}")
+
     # 等待主程序退出，最多 60 秒
     waited = 0.0
     while _pid_exists(pid) and waited < 60.0:
@@ -96,6 +111,7 @@ def main() -> int:
         waited += 0.5
 
     ok = _copy_with_retries(src, dst, retries=15)
+    _log(f"COPY: ok={ok}")
     try:
         os.remove(src)
     except Exception:
@@ -110,10 +126,13 @@ def main() -> int:
     if ok and restart:
         try:
             subprocess.Popen([dst], creationflags=subprocess.DETACHED_PROCESS | subprocess.CREATE_NO_WINDOW)
+            _log("RESTART: started")
         except Exception:
+            _log("RESTART: failed")
             pass
         return 0
 
+    _log("DONE: failed")
     return 4