diff --git a/src-tauri/src/core_runtime.rs b/src-tauri/src/core_runtime.rs
index 2c0e634..91feb31 100644
--- a/src-tauri/src/core_runtime.rs
+++ b/src-tauri/src/core_runtime.rs
@@ -2,6 +2,51 @@ use super::*;
 
 pub(crate) static CORE_OPERATION_LOCK: Mutex<()> = Mutex::new(());
 
+pub(crate) fn lock_core_operation(
+    process_state: &CoreProcessState,
+) -> Result<std::sync::MutexGuard<'static, ()>, String> {
+    let guard = CORE_OPERATION_LOCK
+        .try_lock()
+        .map_err(|_| "内核正在执行其他操作，请稍后重试".to_string())?;
+    process_state.ensure_active()?;
+    Ok(guard)
+}
+
+// Own the guard from spawn, including while the management port is starting.
+pub(crate) struct CoreChild {
+    child: Child,
+    #[cfg(windows)]
+    job: isize,
+}
+
+impl std::ops::Deref for CoreChild {
+    type Target = Child;
+
+    fn deref(&self) -> &Child {
+        &self.child
+    }
+}
+
+impl std::ops::DerefMut for CoreChild {
+    fn deref_mut(&mut self) -> &mut Child {
+        &mut self.child
+    }
+}
+
+impl Drop for CoreChild {
+    fn drop(&mut self) {
+        #[cfg(windows)]
+        {
+            close_windows_handle(self.job);
+            let _ = self.child.wait();
+        }
+        #[cfg(not(windows))]
+        if !matches!(self.child.try_wait(), Ok(Some(_))) {
+            let _ = terminate_child(&mut self.child);
+        }
+    }
+}
+
 #[cfg(any(target_os = "linux", test))]
 struct CoreSpawnRequest {
     command: Command,
@@ -30,19 +75,36 @@ static CORE_PROCESS_SPAWNER: LazyLock<Result<std::sync::mpsc::Sender<CoreSpawnRe
         Ok(sender)
     });
 
-pub(crate) fn spawn_core_child(command: Command) -> Result<Child, String> {
+pub(crate) fn spawn_core_child(command: Command) -> Result<CoreChild, String> {
     #[cfg(target_os = "linux")]
-    {
-        spawn_core_child_on_lifetime_thread(command)
-    }
+    let child = spawn_core_child_on_lifetime_thread(command)?;
 
     #[cfg(not(target_os = "linux"))]
-    {
+    let child = {
         let mut command = command;
         command
             .spawn()
-            .map_err(|error| format!("启动 CPA 内核失败: {error}"))
-    }
+            .map_err(|error| format!("启动 CPA 内核失败: {error}"))?
+    };
+
+    #[cfg(windows)]
+    let job = match attach_child_to_windows_job(&child) {
+        Ok(job) => job,
+        Err(error) => {
+            let mut child = child;
+            return match terminate_child(&mut child) {
+                Ok(()) => Err(error),
+                Err(cleanup_error) => Err(format!(
+                    "{error}；清理未托管的内核进程也失败: {cleanup_error}"
+                )),
+            };
+        }
+    };
+    Ok(CoreChild {
+        child,
+        #[cfg(windows)]
+        job,
+    })
 }
 
 #[cfg(any(target_os = "linux", test))]
@@ -63,9 +125,7 @@ async fn run_core_command(
     operation: fn(&CoreProcessState, &GuiConfigState) -> Result<CoreStatus, String>,
 ) -> Result<CoreStatus, String> {
     tauri::async_runtime::spawn_blocking(move || {
-        let _guard = CORE_OPERATION_LOCK
-            .try_lock()
-            .map_err(|_| "内核正在执行其他操作，请稍后重试".to_string())?;
+        let _guard = lock_core_operation(app.state::<CoreProcessState>().inner())?;
         let status = operation(
             app.state::<CoreProcessState>().inner(),
             app.state::<GuiConfigState>().inner(),
@@ -120,9 +180,7 @@ pub(crate) async fn install_bundled_core(
     window: tauri::Window,
 ) -> Result<CoreInstallResult, String> {
     tauri::async_runtime::spawn_blocking(move || {
-        let _guard = CORE_OPERATION_LOCK
-            .try_lock()
-            .map_err(|_| "内核正在执行其他操作，请稍后重试".to_string())?;
+        let _guard = lock_core_operation(app.state::<CoreProcessState>().inner())?;
         let state = app.state::<CoreDownloadState>();
         let process_state = app.state::<CoreProcessState>();
         let gui_config_state = app.state::<GuiConfigState>();
@@ -190,9 +248,7 @@ pub(crate) async fn install_core_version(
     version: Option<String>,
 ) -> Result<CoreInstallResult, String> {
     tauri::async_runtime::spawn_blocking(move || {
-        let _guard = CORE_OPERATION_LOCK
-            .try_lock()
-            .map_err(|_| "内核正在执行其他操作，请稍后重试".to_string())?;
+        let _guard = lock_core_operation(app.state::<CoreProcessState>().inner())?;
         let state = app.state::<CoreDownloadState>();
         let process_state = app.state::<CoreProcessState>();
         let gui_config_state = app.state::<GuiConfigState>();
@@ -256,10 +312,21 @@ fn pause_core_for_install(
     process_state: &CoreProcessState,
     config: &GuiConfigFile,
 ) -> Result<bool, String> {
-    let was_running = current_core_status(Some(process_state), Some(config.port))?.running;
+    let was_running = pause_core_process_for_install(process_state)?;
+    if was_running {
+        emit_current_core_status(app, process_state, config.port);
+    }
+    Ok(was_running)
+}
+
+pub(crate) fn pause_core_process_for_install(
+    process_state: &CoreProcessState,
+) -> Result<bool, String> {
+    process_state.ensure_active()?;
+    // A process can hold files even when its HTTP port is not responding.
+    let was_running = current_core_status(Some(process_state), None)?.running;
     if was_running {
         stop_core_process_inner(process_state)?;
-        emit_current_core_status(app, process_state, config.port);
     }
     Ok(was_running)
 }
@@ -271,7 +338,7 @@ fn restore_core_after_install<T>(
     was_running: bool,
     install_result: Result<T, String>,
 ) -> Result<T, String> {
-    let restart_result = if was_running {
+    let restart_result = if was_running && !process_state.is_shutting_down() {
         start_core_process_inner(process_state, config)
     } else {
         Ok(())
@@ -344,7 +411,9 @@ pub(crate) fn restart_core_process_with_state(
     gui_config_state: &GuiConfigState,
 ) -> Result<CoreStatus, String> {
     let config = gui_config_state.snapshot()?;
-    let _ = stop_core_process_inner(process_state);
+    if current_core_status(Some(process_state), None)?.running {
+        stop_core_process_inner(process_state)?;
+    }
     start_core_process_inner(process_state, &config)?;
     if let Err(error) = gui_config_state.set_run_on_startup(true) {
         let _ = stop_core_process_inner(process_state);
@@ -1202,6 +1271,7 @@ fn core_management_address(listen_host: &str, port: u16) -> Result<SocketAddr, S
 }
 
 pub(crate) enum CoreStartupFailure {
+    ShuttingDown,
     Exited(std::process::ExitStatus),
     Spawn(String),
     StatusCheck(io::Error),
@@ -1228,6 +1298,7 @@ impl CoreStartupFailure {
 impl std::fmt::Display for CoreStartupFailure {
     fn fmt(&self, formatter: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         match self {
+            Self::ShuttingDown => formatter.write_str("应用正在退出，已取消内核启动"),
             Self::Exited(status) => write!(formatter, "CPA 内核启动后立即退出: {status}"),
             Self::Spawn(error) => formatter.write_str(error),
             Self::StatusCheck(error) => write!(formatter, "检查 CPA 内核启动状态失败: {error}"),
@@ -1299,12 +1370,13 @@ impl CoreStartAttemptFailure {
 }
 
 fn start_core_process_once(
+    process_state: &CoreProcessState,
     binary_path: &Path,
     config_path: &str,
     install_dir: &Path,
     log_path: &Path,
     management_address: SocketAddr,
-) -> Result<Child, CoreStartAttemptFailure> {
+) -> Result<CoreChild, CoreStartAttemptFailure> {
     let mut command = Command::new(binary_path);
     command
         .args(["-config", config_path])
@@ -1331,7 +1403,7 @@ fn start_core_process_once(
             });
         }
     };
-    match wait_for_core_management_port(&mut child, management_address) {
+    match wait_for_core_management_port(&mut child, management_address, process_state) {
         Ok(()) => Ok(child),
         Err(failure) => {
             if !failure.child_has_exited() {
@@ -1346,6 +1418,7 @@ pub(crate) fn start_core_process_inner(
     process_state: &CoreProcessState,
     gui_config: &GuiConfigFile,
 ) -> Result<(), String> {
+    process_state.ensure_active()?;
     let install_dir = core_install_dir()?;
     if !gui_config.auth_dir.trim().is_empty() {
         let auth_dir = auth_dir_path_for_core(&gui_config.auth_dir, &install_dir);
@@ -1375,6 +1448,7 @@ pub(crate) fn start_core_process_inner(
     let log_path = core_start_log_path(&install_dir, &gui_config.auth_dir);
     let start_once = || {
         start_core_process_once(
+            process_state,
             &binary_path,
             &config_path,
             &install_dir,
@@ -1416,9 +1490,13 @@ pub(crate) fn start_core_process_inner(
 pub(crate) fn wait_for_core_management_port(
     child: &mut Child,
     address: SocketAddr,
+    process_state: &CoreProcessState,
 ) -> Result<(), CoreStartupFailure> {
     let deadline = Instant::now() + Duration::from_secs(10);
     loop {
+        if process_state.is_shutting_down() {
+            return Err(CoreStartupFailure::ShuttingDown);
+        }
         if let Some(status) = child.try_wait().map_err(CoreStartupFailure::StatusCheck)? {
             return Err(CoreStartupFailure::Exited(status));
         }
@@ -1500,7 +1578,6 @@ pub(crate) fn stop_core_process_inner(process_state: &CoreProcessState) -> Resul
         if let Err(error) = terminate_child(&mut child) {
             errors.push(error);
         }
-        process_state.clear_lifetime_guard();
     }
 
     let mut process_ids = process_state
@@ -2113,8 +2190,14 @@ pub(crate) fn shutdown_managed_core(
             .ok()
             .and_then(|install_dir| find_core_binary(&install_dir))
             .is_some_and(|binary_path| is_core_running(&binary_path));
-    let _ = gui_config_state.set_run_on_startup(was_running);
-    let _ = stop_core_process_inner(process_state);
+    if was_running {
+        if let Err(error) = stop_core_process_inner(process_state) {
+            eprintln!("退出时关闭 CPA 内核失败: {error}");
+        }
+    }
+    if let Err(error) = gui_config_state.set_run_on_startup(was_running) {
+        eprintln!("保存退出前的内核状态失败: {error}");
+    }
 }
 
 #[cfg(windows)]
@@ -2173,6 +2256,13 @@ pub(crate) fn close_windows_handle(handle: isize) {
 }
 
 pub(crate) fn terminate_child(child: &mut Child) -> Result<(), String> {
+    if child
+        .try_wait()
+        .map_err(|error| format!("检查 CPA 内核进程状态失败: {error}"))?
+        .is_some()
+    {
+        return Ok(());
+    }
     #[cfg(windows)]
     {
         child
@@ -2211,10 +2301,31 @@ pub(crate) fn terminate_child(child: &mut Child) -> Result<(), String> {
 pub(crate) fn terminate_process_id(process_id: u32) -> Result<(), String> {
     #[cfg(windows)]
     {
-        let process_id = process_id.to_string();
+        use std::os::windows::io::{AsRawHandle, FromRawHandle, OwnedHandle};
+        use windows_sys::Win32::{
+            Foundation::{ERROR_INVALID_PARAMETER, WAIT_OBJECT_0, WAIT_TIMEOUT},
+            System::Threading::{OpenProcess, WaitForSingleObject, PROCESS_SYNCHRONIZE},
+        };
+
+        // Keep a handle to this process until it is signalled. taskkill exiting
+        // successfully only means termination was requested, not that file
+        // handles have been released.
+        let handle = unsafe { OpenProcess(PROCESS_SYNCHRONIZE, 0, process_id) };
+        if handle.is_null() {
+            let error = io::Error::last_os_error();
+            if error.raw_os_error() == Some(ERROR_INVALID_PARAMETER as i32) {
+                return Ok(());
+            }
+            return Err(format!("打开 CPA 内核进程失败: PID {process_id}: {error}"));
+        }
+        let handle = unsafe { OwnedHandle::from_raw_handle(handle) };
+        let raw_handle = handle.as_raw_handle();
+        if unsafe { WaitForSingleObject(raw_handle, 0) } == WAIT_OBJECT_0 {
+            return Ok(());
+        }
         let mut command = Command::new("taskkill");
         command
-            .args(["/PID", &process_id, "/T", "/F"])
+            .args(["/PID", &process_id.to_string(), "/T", "/F"])
             .stdin(Stdio::null())
             .stdout(Stdio::null())
             .stderr(Stdio::null());
@@ -2222,11 +2333,15 @@ pub(crate) fn terminate_process_id(process_id: u32) -> Result<(), String> {
         let status = command
             .status()
             .map_err(|err| format!("关闭 CPA 内核进程失败: {err}"))?;
-
-        if status.success() {
-            Ok(())
-        } else {
-            Err(format!("关闭 CPA 内核进程失败: PID {process_id}"))
+        let wait =
+            unsafe { WaitForSingleObject(raw_handle, if status.success() { 10_000 } else { 0 }) };
+        match wait {
+            WAIT_OBJECT_0 => Ok(()),
+            WAIT_TIMEOUT => Err(format!("CPA 内核进程未退出: PID {process_id}")),
+            _ => Err(format!(
+                "等待 CPA 内核进程退出失败: PID {process_id}: {}",
+                io::Error::last_os_error()
+            )),
         }
     }
 
diff --git a/src-tauri/src/main.rs b/src-tauri/src/main.rs
index cb0e353..a8b7ca1 100644
--- a/src-tauri/src/main.rs
+++ b/src-tauri/src/main.rs
@@ -303,11 +303,11 @@ struct AppUpdateInner {
 
 #[derive(Default)]
 struct CoreProcessState {
-    child: Mutex<Option<Child>>,
+    child: Mutex<Option<CoreChild>>,
     adopted_processes: Mutex<Vec<AdoptedCoreProcess>>,
     starting: AtomicBool,
-    #[cfg(windows)]
-    job: Mutex<Option<isize>>,
+    shutting_down: AtomicBool,
+    shutdown_complete: AtomicBool,
 }
 
 #[derive(Default)]
@@ -1739,8 +1739,20 @@ impl CoreProcessState {
             child: Mutex::new(None),
             adopted_processes: Mutex::new(Vec::new()),
             starting: AtomicBool::new(starting),
-            #[cfg(windows)]
-            job: Mutex::new(None),
+            shutting_down: AtomicBool::new(false),
+            shutdown_complete: AtomicBool::new(false),
+        }
+    }
+
+    fn is_shutting_down(&self) -> bool {
+        self.shutting_down.load(Ordering::Acquire)
+    }
+
+    fn ensure_active(&self) -> Result<(), String> {
+        if self.is_shutting_down() {
+            Err("应用正在退出，已取消内核操作".to_string())
+        } else {
+            Ok(())
         }
     }
 
@@ -1760,8 +1772,6 @@ impl CoreProcessState {
                 }
 
                 *child = None;
-                drop(child);
-                self.clear_lifetime_guard();
             }
         }
 
@@ -1778,16 +1788,7 @@ impl CoreProcessState {
             })
     }
 
-    fn clear_lifetime_guard(&self) {
-        #[cfg(windows)]
-        if let Ok(mut job) = self.job.lock() {
-            if let Some(handle) = job.take() {
-                close_windows_handle(handle);
-            }
-        }
-    }
-
-    fn take_child(&self) -> Option<Child> {
+    fn take_child(&self) -> Option<CoreChild> {
         self.child.lock().ok().and_then(|mut child| child.take())
     }
 
@@ -1823,55 +1824,15 @@ impl CoreProcessState {
             .unwrap_or_default()
     }
 
-    fn store_child(&self, child: Child) -> Result<u32, String> {
+    fn store_child(&self, child: CoreChild) -> Result<u32, String> {
+        self.ensure_active()?;
         let pid = child.id();
         self.clear_adopted_processes()?;
-
-        #[cfg(windows)]
-        {
-            let job = match attach_child_to_windows_job(&child) {
-                Ok(job) => job,
-                Err(error) => {
-                    let mut child = child;
-                    let cleanup_error = terminate_child(&mut child).err();
-                    return Err(match cleanup_error {
-                        Some(cleanup_error) => {
-                            format!("{error}；清理未托管的内核进程也失败: {cleanup_error}")
-                        }
-                        None => error,
-                    });
-                }
-            };
-            let Ok(mut managed_child) = self.child.lock() else {
-                close_windows_handle(job);
-                return Err("内核进程状态锁已损坏".to_string());
-            };
-            let Ok(mut managed_job) = self.job.lock() else {
-                close_windows_handle(job);
-                return Err("内核进程作业状态锁已损坏".to_string());
-            };
-            *managed_child = Some(child);
-            *managed_job = Some(job);
-        }
-
-        #[cfg(not(windows))]
-        {
-            let mut managed_child = match self.child.lock() {
-                Ok(managed_child) => managed_child,
-                Err(_) => {
-                    let mut child = child;
-                    let cleanup_error = terminate_child(&mut child).err();
-                    return Err(match cleanup_error {
-                        Some(cleanup_error) => format!(
-                            "内核进程状态锁已损坏；清理未托管的内核进程也失败: {cleanup_error}"
-                        ),
-                        None => "内核进程状态锁已损坏".to_string(),
-                    });
-                }
-            };
-            *managed_child = Some(child);
-        }
-
+        let mut managed_child = self
+            .child
+            .lock()
+            .map_err(|_| "内核进程状态锁已损坏".to_string())?;
+        *managed_child = Some(child);
         Ok(pid)
     }
 }
@@ -2448,6 +2409,10 @@ fn main() {
                 };
                 let gui_config_state = core_app.state::<GuiConfigState>();
                 let process_state = core_app.state::<CoreProcessState>();
+                if process_state.ensure_active().is_err() {
+                    process_state.set_starting(false);
+                    return;
+                }
                 let Ok(config) = gui_config_state.snapshot() else {
                     process_state.set_starting(false);
                     return;
@@ -2623,10 +2588,34 @@ fn main() {
             has_visible_windows: false,
             ..
         } => show_main_window(app_handle),
-        tauri::RunEvent::ExitRequested { .. } => {
+        tauri::RunEvent::ExitRequested { api, code, .. } => {
+            let process_state = app_handle.state::<CoreProcessState>();
+            if process_state.shutdown_complete.load(Ordering::Acquire) {
+                return;
+            }
+            api.prevent_exit();
+            if process_state.shutting_down.swap(true, Ordering::AcqRel) {
+                return;
+            }
             if let Err(error) = persist_main_window_size(app_handle) {
                 eprintln!("保存主窗口尺寸失败: {error}");
             }
+            app_handle.state::<CoreDownloadState>().cancel();
+            let app_handle = app_handle.clone();
+            // Keep the event loop alive while an in-flight operation finishes:
+            // tray/status updates from that operation may need the UI thread.
+            tauri::async_runtime::spawn_blocking(move || {
+                let _guard = CORE_OPERATION_LOCK
+                    .lock()
+                    .unwrap_or_else(|error| error.into_inner());
+                let process_state = app_handle.state::<CoreProcessState>();
+                let gui_config_state = app_handle.state::<GuiConfigState>();
+                shutdown_managed_core(process_state.inner(), gui_config_state.inner());
+                process_state
+                    .shutdown_complete
+                    .store(true, Ordering::Release);
+                app_handle.exit(code.unwrap_or(0));
+            });
         }
         tauri::RunEvent::Exit => {
             usage::stop_usage_collector(app_handle);
@@ -2636,7 +2625,10 @@ fn main() {
             }
             let gui_config_state = app_handle.state::<GuiConfigState>();
             let process_state = app_handle.state::<CoreProcessState>();
-            shutdown_managed_core(process_state.inner(), gui_config_state.inner());
+            if !process_state.shutdown_complete.load(Ordering::Acquire) {
+                process_state.shutting_down.store(true, Ordering::Release);
+                shutdown_managed_core(process_state.inner(), gui_config_state.inner());
+            }
         }
         _ => {}
     });
diff --git a/src-tauri/src/tests/core_runtime.rs b/src-tauri/src/tests/core_runtime.rs
index 988b93f..6946b7d 100644
--- a/src-tauri/src/tests/core_runtime.rs
+++ b/src-tauri/src/tests/core_runtime.rs
@@ -50,7 +50,7 @@ fn core_child_sleep_command() -> Command {
     command
 }
 
-fn assert_core_child_survives(mut child: Child) {
+fn assert_core_child_survives(child: &mut Child) {
     thread::sleep(Duration::from_millis(200));
     let status = child.try_wait();
     let _ = child.kill();
@@ -60,10 +60,10 @@ fn assert_core_child_survives(mut child: Child) {
 
 #[test]
 fn core_child_survives_launcher_thread_exit() {
-    let child = thread::spawn(|| spawn_core_child(core_child_sleep_command()).unwrap())
+    let mut child = thread::spawn(|| spawn_core_child(core_child_sleep_command()).unwrap())
         .join()
         .unwrap();
-    assert_core_child_survives(child);
+    assert_core_child_survives(&mut child);
 }
 
 #[test]
@@ -71,25 +71,152 @@ fn core_child_survives_blocking_runtime_shutdown() {
     let runtime = tokio::runtime::Builder::new_current_thread()
         .build()
         .unwrap();
-    let child = runtime
+    let mut child = runtime
         .block_on(runtime.spawn_blocking(|| spawn_core_child(core_child_sleep_command()).unwrap()))
         .unwrap();
     drop(runtime);
-    assert_core_child_survives(child);
+    assert_core_child_survives(&mut child);
 }
 
 #[test]
 fn core_child_spawner_remains_available_after_spawn_failure() {
     let missing_binary = agent_test_home("missing-core-spawner-binary").join(core_binary_name());
     assert!(spawn_core_child_on_lifetime_thread(Command::new(missing_binary)).is_err());
-    let child =
+    let mut child =
         thread::spawn(|| spawn_core_child_on_lifetime_thread(core_child_sleep_command()).unwrap())
             .join()
             .unwrap();
-    assert_core_child_survives(child);
+    assert_core_child_survives(&mut child);
 }
 
-#[cfg(target_os = "linux")]
+#[test]
+fn exiting_during_core_startup_cancels_the_port_wait() {
+    let state = std::sync::Arc::new(CoreProcessState::new(true));
+    let listener = std::net::TcpListener::bind("127.0.0.1:0").unwrap();
+    let address = listener.local_addr().unwrap();
+    drop(listener);
+    let mut child = spawn_core_child(core_child_sleep_command()).unwrap();
+    let child_id = child.id();
+    let exiting_state = state.clone();
+    let exit = thread::spawn(move || {
+        thread::sleep(Duration::from_millis(100));
+        exiting_state.shutting_down.store(true, Ordering::Release);
+    });
+
+    let started = Instant::now();
+    let result = wait_for_core_management_port(&mut child, address, &state);
+    drop(child);
+    exit.join().unwrap();
+    assert!(matches!(result, Err(CoreStartupFailure::ShuttingDown)));
+    assert!(started.elapsed() < Duration::from_secs(2));
+    assert!(!is_process_alive(child_id));
+}
+
+#[test]
+fn exiting_rejects_new_core_operations_and_cleans_up_an_in_flight_child() {
+    let state = CoreProcessState::new(false);
+    let child = spawn_core_child(core_child_sleep_command()).unwrap();
+    let child_id = child.id();
+    state.shutting_down.store(true, Ordering::Release);
+
+    assert!(lock_core_operation(&state)
+        .unwrap_err()
+        .contains("应用正在退出"));
+    assert!(state
+        .store_child(child)
+        .unwrap_err()
+        .contains("应用正在退出"));
+    assert!(!is_process_alive(child_id));
+    assert_eq!(state.managed_pid(), None);
+}
+
+#[cfg(windows)]
+#[test]
+fn core_config_file_lock_helper() {
+    use std::os::windows::fs::OpenOptionsExt;
+    use windows_sys::Win32::Storage::FileSystem::{FILE_SHARE_READ, FILE_SHARE_WRITE};
+
+    let Some(path) = env::var_os("EASYCLIPROXYAPI_CORE_FILE_LOCK_TEST_HELPER") else {
+        return;
+    };
+    let _file = File::options()
+        .read(true)
+        .share_mode(FILE_SHARE_READ | FILE_SHARE_WRITE)
+        .open(path)
+        .unwrap();
+    println!("CORE_FILE_LOCKED");
+    io::stdout().flush().unwrap();
+    thread::sleep(Duration::from_secs(10));
+}
+
+#[cfg(windows)]
+#[test]
+fn updating_stops_an_adopted_core_without_a_port_before_replacing_its_config() {
+    use std::io::BufRead;
+
+    let root = agent_test_home("core-stop-before-replace");
+    let config_path = root.join(CORE_CONFIG_FILE);
+    let replacement = root.join("new-config.yaml");
+    fs::write(&config_path, b"old config").unwrap();
+    fs::write(&replacement, b"new config").unwrap();
+    let binary_path = env::current_exe().unwrap();
+    let mut command = Command::new(&binary_path);
+    command
+        .args([
+            "--exact",
+            "tests::core_runtime::core_config_file_lock_helper",
+            "--nocapture",
+        ])
+        .env("EASYCLIPROXYAPI_CORE_FILE_LOCK_TEST_HELPER", &config_path)
+        .stdin(Stdio::null())
+        .stdout(Stdio::piped())
+        .stderr(Stdio::null());
+    configure_background_command(&mut command);
+    // Spawn without the GUI's job guard to simulate a previous orphan.
+    let mut child = command.spawn().unwrap();
+    let output = io::BufReader::new(child.stdout.take().unwrap());
+    let ready = output
+        .lines()
+        .any(|line| line.unwrap() == "CORE_FILE_LOCKED");
+    let state = CoreProcessState::new(false);
+    state
+        .adopt_process_ids(&binary_path, vec![child.id()])
+        .unwrap();
+    let listener = std::net::TcpListener::bind("127.0.0.1:0").unwrap();
+    let port = listener.local_addr().unwrap().port();
+    drop(listener);
+
+    let status = current_core_status(Some(&state), Some(port)).unwrap();
+    let locked_result = copy_core_file_replace(&replacement, &config_path);
+    let stopped = pause_core_process_for_install(&state);
+    let exited = child.try_wait().unwrap().is_some();
+    let replace_result = copy_core_file_replace(&replacement, &config_path);
+    let _ = child.kill();
+    let _ = child.wait();
+
+    assert!(ready);
+    assert!(
+        !status.running,
+        "the orphan has no listening management port"
+    );
+    assert!(
+        locked_result.is_err(),
+        "the orphan must hold a real Windows file lock"
+    );
+    assert!(
+        stopped.unwrap(),
+        "the update must stop the orphan despite the closed port"
+    );
+    assert!(
+        exited,
+        "stopping must wait until the process has actually exited"
+    );
+    replace_result.unwrap();
+    assert_eq!(fs::read(&config_path).unwrap(), b"new config");
+    fs::remove_dir_all(root).unwrap();
+}
+
+#[cfg(any(target_os = "linux", windows))]
 #[test]
 fn core_child_owner_process_helper() {
     if env::var_os("EASYCLIPROXYAPI_CORE_OWNER_TEST_HELPER").is_none() {
@@ -103,7 +230,7 @@ fn core_child_owner_process_helper() {
     thread::sleep(Duration::from_secs(10));
 }
 
-#[cfg(target_os = "linux")]
+#[cfg(any(target_os = "linux", windows))]
 #[test]
 fn core_child_stops_when_owner_process_is_killed() {
     use std::io::BufRead;
diff --git a/src-tauri/src/tray.rs b/src-tauri/src/tray.rs
index edaf68c..1907270 100644
--- a/src-tauri/src/tray.rs
+++ b/src-tauri/src/tray.rs
@@ -473,6 +473,7 @@ pub(crate) fn run_windows_tray_core_action(
         let process_state = app_handle.state::<CoreProcessState>();
         let gui_config_state = app_handle.state::<GuiConfigState>();
         let result = (|| -> Result<CoreStatus, String> {
+            let _guard = lock_core_operation(process_state.inner())?;
             match action {
                 WindowsTrayCoreAction::Toggle => {
                     let config = gui_config_state.snapshot()?;