diff --git a/openless-all/app/windows-ime/src/ipc_client.cpp b/openless-all/app/windows-ime/src/ipc_client.cpp
index 55c42d15..91767008 100644
--- a/openless-all/app/windows-ime/src/ipc_client.cpp
+++ b/openless-all/app/windows-ime/src/ipc_client.cpp
@@ -336,10 +336,15 @@ std::wstring EscapeJsonString(const std::wstring& value) {
 
 }  // namespace
 
-OpenLessPipeServer::OpenLessPipeServer() = default;
+OpenLessPipeServer::OpenLessPipeServer()
+    : shutdown_event_(CreateEventW(nullptr, TRUE, FALSE, nullptr)) {}
 
 OpenLessPipeServer::~OpenLessPipeServer() {
   Stop();
+  if (shutdown_event_ != nullptr) {
+    CloseHandle(shutdown_event_);
+    shutdown_event_ = nullptr;
+  }
 }
 
 void OpenLessPipeServer::Start(OpenLessTextService* service) {
@@ -348,6 +353,11 @@ void OpenLessPipeServer::Start(OpenLessTextService* service) {
   }
 
   stop_requested_.store(false);
+
+  if (shutdown_event_ != nullptr) {
+    ResetEvent(shutdown_event_);
+  }
+
   pipe_name_ = PipeNameForCurrentThread();
   service_ = service;
   service_->AddRef();
@@ -356,12 +366,21 @@ void OpenLessPipeServer::Start(OpenLessTextService* service) {
 
 void OpenLessPipeServer::Stop() {
   stop_requested_.store(true);
+
+  if (shutdown_event_ != nullptr) {
+    SetEvent(shutdown_event_);
+  }
+
   if (thread_.joinable()) {
     CancelSynchronousIo(thread_.native_handle());
     WakePipe();
     thread_.join();
   }
 
+  if (shutdown_event_ != nullptr) {
+    ResetEvent(shutdown_event_);
+  }
+
   if (service_ != nullptr) {
     service_->Release();
     service_ = nullptr;
@@ -458,7 +477,8 @@ void OpenLessPipeServer::HandleSubmitLine(HANDLE pipe, const std::string& line)
   }
 
   const HRESULT hr =
-      service_->SubmitTextFromPipe(message.session_id, message.text);
+      service_->SubmitTextFromPipe(message.session_id, message.text,
+                                   shutdown_event_);
   if (SUCCEEDED(hr)) {
     WriteResult(pipe, message.session_id, L"committed", nullptr);
   } else {
diff --git a/openless-all/app/windows-ime/src/ipc_client.h b/openless-all/app/windows-ime/src/ipc_client.h
index 909be569..e6d10646 100644
--- a/openless-all/app/windows-ime/src/ipc_client.h
+++ b/openless-all/app/windows-ime/src/ipc_client.h
@@ -32,6 +32,7 @@ class OpenLessPipeServer {
   std::thread thread_;
   std::mutex pipe_mutex_;
   HANDLE pipe_handle_ = INVALID_HANDLE_VALUE;
+  HANDLE shutdown_event_ = nullptr;
   std::wstring pipe_name_;
   OpenLessTextService* service_ = nullptr;
 };
diff --git a/openless-all/app/windows-ime/src/text_service.cpp b/openless-all/app/windows-ime/src/text_service.cpp
index f303eac1..af3bee49 100644
--- a/openless-all/app/windows-ime/src/text_service.cpp
+++ b/openless-all/app/windows-ime/src/text_service.cpp
@@ -1,5 +1,6 @@
 #include "text_service.h"
 
+#include <atomic>
 #include <memory>
 #include <new>
 
@@ -15,11 +16,25 @@ constexpr UINT kSubmitTextMessage = WM_APP + 1;
 constexpr UINT kSubmitTextTimeoutMs = 2000;
 
 struct SubmitTextRequest {
-  const std::wstring* session_id = nullptr;
-  const std::wstring* text = nullptr;
+  // Owned copies — not pointers into another thread's stack.
+  std::wstring session_id;
+  std::wstring text;
   std::shared_ptr<OpenLessAsyncEditState> async_completion;
   bool wait_for_async_completion = false;
   HRESULT result = E_UNEXPECTED;
+  HANDLE completion_event = nullptr;
+  // Two owners at creation: pipe thread (waiting on completion_event) and
+  // the queued window message.  Each owner calls Release() when done; the
+  // last one to Release() closes the event and deletes the request.
+  std::atomic<int> ref_count{2};
+  void Release() {
+    if (ref_count.fetch_sub(1, std::memory_order_acq_rel) == 1) {
+      if (completion_event != nullptr) {
+        CloseHandle(completion_event);
+      }
+      delete this;
+    }
+  }
 };
 
 HRESULT WaitForAsyncEditCompletion(
@@ -133,7 +148,8 @@ STDMETHODIMP OpenLessTextService::Deactivate() {
 
 HRESULT OpenLessTextService::SubmitTextFromPipe(
     const std::wstring& session_id,
-    const std::wstring& text) {
+    const std::wstring& text,
+    HANDLE shutdown_event) {
   if (GetCurrentThreadId() == owner_thread_id_) {
     return CommitTextOnOwnerThread(session_id, text, nullptr, nullptr);
   }
@@ -142,24 +158,60 @@ HRESULT OpenLessTextService::SubmitTextFromPipe(
     return E_UNEXPECTED;
   }
 
-  SubmitTextRequest request;
-  request.session_id = &session_id;
-  request.text = &text;
-  DWORD_PTR message_result = 0;
-  const LRESULT sent = SendMessageTimeoutW(
-      message_window_, kSubmitTextMessage, 0,
-      reinterpret_cast<LPARAM>(&request), SMTO_ABORTIFHUNG,
-      kSubmitTextTimeoutMs, &message_result);
-  if (sent == 0) {
+  auto* request = new (std::nothrow) SubmitTextRequest;
+  if (request == nullptr) {
+    return E_OUTOFMEMORY;
+  }
+
+  request->session_id = session_id;
+  request->text = text;
+  request->completion_event =
+      CreateEventW(nullptr, TRUE, FALSE, nullptr);
+  if (request->completion_event == nullptr) {
+    delete request;
+    return HRESULT_FROM_WIN32(GetLastError());
+  }
+
+  if (!PostMessageW(message_window_, kSubmitTextMessage, 0,
+                    reinterpret_cast<LPARAM>(request))) {
     const DWORD error = GetLastError();
-    return HRESULT_FROM_WIN32(error != ERROR_SUCCESS ? error : ERROR_TIMEOUT);
+    CloseHandle(request->completion_event);
+    delete request;
+    return HRESULT_FROM_WIN32(error);
   }
 
-  if (request.wait_for_async_completion) {
-    return WaitForAsyncEditCompletion(request.async_completion);
+  HANDLE wait_handles[2] = {};
+  DWORD wait_count = 0;
+
+  wait_handles[wait_count] = request->completion_event;
+  ++wait_count;
+
+  if (shutdown_event != nullptr) {
+    wait_handles[wait_count] = shutdown_event;
+    ++wait_count;
   }
 
-  return request.result;
+  const DWORD wait_result = WaitForMultipleObjects(
+      wait_count, wait_handles, FALSE, kSubmitTextTimeoutMs);
+
+  HRESULT result;
+  if (wait_result == WAIT_OBJECT_0) {
+    result = request->result;
+    if (request->wait_for_async_completion) {
+      result = WaitForAsyncEditCompletion(request->async_completion);
+    }
+  } else if (wait_count > 1 && wait_result == WAIT_OBJECT_0 + 1) {
+    result = HRESULT_FROM_WIN32(ERROR_CANCELLED);
+  } else if (wait_result == WAIT_TIMEOUT) {
+    result = HRESULT_FROM_WIN32(ERROR_TIMEOUT);
+  } else {
+    result = HRESULT_FROM_WIN32(GetLastError());
+  }
+
+  // Release the pipe-thread reference.  The message-thread reference, if
+  // still outstanding (timeout / shutdown paths), will clean up later.
+  request->Release();
+  return result;
 }
 
 HRESULT OpenLessTextService::StartIpcServer() {
@@ -200,6 +252,18 @@ HRESULT OpenLessTextService::EnsureMessageWindow() {
 
 void OpenLessTextService::DestroyMessageWindow() {
   if (message_window_ != nullptr) {
+    // Drain any kSubmitTextMessage still in the queue so the associated
+    // SubmitTextRequest references are released before the window is gone.
+    // These are left over when SubmitTextFromPipe exited via timeout or
+    // shutdown before the owner thread could dispatch the message.
+    MSG msg;
+    while (PeekMessageW(&msg, message_window_, kSubmitTextMessage,
+                        kSubmitTextMessage, PM_REMOVE)) {
+      auto* request = reinterpret_cast<SubmitTextRequest*>(msg.lParam);
+      if (request != nullptr) {
+        request->Release();
+      }
+    }
     DestroyWindow(message_window_);
     message_window_ = nullptr;
   }
@@ -317,14 +381,21 @@ LRESULT CALLBACK OpenLessTextService::MessageWindowProc(HWND window,
       GetWindowLongPtrW(window, GWLP_USERDATA));
   if (message == kSubmitTextMessage && service != nullptr) {
     auto* request = reinterpret_cast<SubmitTextRequest*>(lparam);
-    if (request == nullptr || request->session_id == nullptr ||
-        request->text == nullptr) {
+    if (request == nullptr || request->session_id.empty() ||
+        request->text.empty()) {
+      if (request != nullptr) {
+        request->Release();
+      }
       return 0;
     }
 
     request->result = service->CommitTextOnOwnerThread(
-        *request->session_id, *request->text, &request->async_completion,
+        request->session_id, request->text, &request->async_completion,
         &request->wait_for_async_completion);
+    if (request->completion_event != nullptr) {
+      SetEvent(request->completion_event);
+    }
+    request->Release();
     return 1;
   }
 
diff --git a/openless-all/app/windows-ime/src/text_service.h b/openless-all/app/windows-ime/src/text_service.h
index c69190d0..b47323cb 100644
--- a/openless-all/app/windows-ime/src/text_service.h
+++ b/openless-all/app/windows-ime/src/text_service.h
@@ -27,7 +27,8 @@ class OpenLessTextService final : public ITfTextInputProcessorEx {
                           DWORD flags) override;
 
   HRESULT SubmitTextFromPipe(const std::wstring& session_id,
-                             const std::wstring& text);
+                             const std::wstring& text,
+                             HANDLE shutdown_event = nullptr);
 
  private:
   HRESULT StartIpcServer();