[fix] reduce release log verbosity and enforce single instance

apps/desktop/src/app/main.cpp

@@ -23,6 +23,7 @@
 #include "config_center.h"
 #include "daemon.h"
 #include "path_manager.h"
+#include "platform/single_instance.h"
 #include "rd_log.h"
 #include "render.h"
 
@@ -183,28 +184,34 @@ int HandleServiceCliCommand(const std::string& command) {
 }  // namespace
 #endif
 
-static int RunApplication(int argc, char* argv[]) {
-  // Service operations and config migration can log before the GUI starts.
-  // Configure the directory first, including CLI and daemon child paths.
+static bool IsDaemonChild(int argc, char* argv[]) {
+  for (int i = 1; i < argc; ++i) {
+    if (std::strcmp(argv[i], "--child") == 0) return true;
+  }
+  return false;
+}
+
+static crossdesk::platform::InstanceResult AcquireInstance(
+    crossdesk::platform::SingleInstanceGuard& guard,
+    crossdesk::platform::InstanceRole role) {
+  std::string error;
+  const auto result = guard.TryAcquire(role, error);
+  if (result == crossdesk::platform::InstanceResult::kAlreadyRunning) {
+    std::cerr << "CrossDesk is already running for this user.\n";
+  } else if (result == crossdesk::platform::InstanceResult::kError) {
+    std::cerr << "CrossDesk cannot start: " << error << '\n';
+  }
+  return result;
+}
+
+static int RunApplication(
+    int argc, char* argv[],
+    crossdesk::platform::SingleInstanceGuard& client_instance) {
+  // The instance guards are held before any configuration or logger is opened.
   auto path_manager = std::make_unique<crossdesk::PathManager>("CrossDesk");
   crossdesk::InitLogger(path_manager->GetLogPath().string());
 
-#ifdef _WIN32
-  if (argc > 1 && IsServiceCliCommand(argv[1])) {
-    return HandleServiceCliCommand(argv[1]);
-  }
-#endif
-
-  // check if running as child process
-  bool is_child = false;
-  for (int i = 1; i < argc; i++) {
-    if (strcmp(argv[i], "--child") == 0) {
-      is_child = true;
-      break;
-    }
-  }
-
-  if (is_child) {
+  if (IsDaemonChild(argc, argv)) {
     // child process: run render directly
     crossdesk::Render render;
     return render.Run();
@@ -230,11 +237,23 @@ static int RunApplication(int argc, char* argv[]) {
 #endif
 
   if (enable_daemon) {
+    // The launcher lease stays in main for the supervisor's entire lifetime.
+    // Each --child must acquire its own client lease, so it is neither blocked
+    // by its supervisor nor able to bypass the single-client restriction.
+    client_instance.Release();
     // start daemon with restart monitoring
     Daemon daemon("CrossDesk");
 
     // define main loop function: run render and stop daemon on normal exit
-    Daemon::MainLoopFunc main_loop = [&daemon]() {
+    Daemon::MainLoopFunc main_loop = [&daemon, &client_instance]() {
+      // Executable discovery can fail and make the supervisor run the GUI in
+      // process. This fallback must retain the same client ownership rule.
+      if (AcquireInstance(client_instance,
+                          crossdesk::platform::InstanceRole::kClient) !=
+          crossdesk::platform::InstanceResult::kAcquired) {
+        daemon.stop();
+        return;
+      }
       crossdesk::Render render;
       render.Run();
       daemon.stop();
@@ -267,26 +286,51 @@ int main(int argc, char* argv[]) {
     std::cout << console.Text("console_cli_help");
     return 0;
   }
-  const int result = crossdesk::RunWithLinuxDisplay(
-      argc, argv, [&] { return RunApplication(argc, argv); }, [&] {
+#endif
+#ifdef _WIN32
+  if (argc == 2 &&
+      std::strcmp(argv[1], crossdesk::kSlintRendererProbeArgument) == 0) {
+    return crossdesk::RunSlintRendererProbe();
+  }
+  if (argc > 1 && IsServiceCliCommand(argv[1])) {
+    EnsureConsoleForCli();
+    crossdesk::platform::SingleInstanceGuard cli_instance;
+    if (AcquireInstance(cli_instance, crossdesk::platform::InstanceRole::kServiceCli) !=
+        crossdesk::platform::InstanceResult::kAcquired) return 1;
+    crossdesk::PathManager paths("CrossDesk");
+    crossdesk::InitLogger(paths.GetLogPath().string(), "crossdesk-service-cli");
+    return HandleServiceCliCommand(argv[1]);
+  }
+#endif
+
+  using crossdesk::platform::InstanceResult;
+  using crossdesk::platform::InstanceRole;
+  crossdesk::platform::SingleInstanceGuard launcher_instance;
+  crossdesk::platform::SingleInstanceGuard client_instance;
+  if (!IsDaemonChild(argc, argv)) {
+    const auto result = AcquireInstance(launcher_instance, InstanceRole::kLauncher);
+    if (result != InstanceResult::kAcquired)
+      return result == InstanceResult::kAlreadyRunning ? 0 : 1;
+  }
+  const auto result = AcquireInstance(client_instance, InstanceRole::kClient);
+  if (result != InstanceResult::kAcquired)
+    return result == InstanceResult::kAlreadyRunning ? 0 : 1;
+
+#ifdef __linux__
+  const int exit_code = crossdesk::RunWithLinuxDisplay(
+      argc, argv, [&] { return RunApplication(argc, argv, client_instance); }, [&] {
         crossdesk::PathManager paths("CrossDesk");
         if (console.Enable(paths.GetLogPath(), paths.GetCachePath() / "config.ini")) return true;
         std::cerr << "无法初始化日志或控制台，启动失败。\n";
         return false;
       });
   if (console.active()) {
-    console.Notify(result == 0 ? console.Text("console_exited")
-        : console.Text("console_stopped") + " " + std::to_string(result) +
+    console.Notify(exit_code == 0 ? console.Text("console_exited")
+        : console.Text("console_stopped") + " " + std::to_string(exit_code) +
           "; " + console.Text("console_log_file") + ": " + console.diagnostic_path());
   }
-  return result;
+  return exit_code;
 #else
-#ifdef _WIN32
-  if (argc == 2 &&
-      std::strcmp(argv[1], crossdesk::kSlintRendererProbeArgument) == 0) {
-    return crossdesk::RunSlintRendererProbe();
-  }
-#endif
-  return RunApplication(argc, argv);
+  return RunApplication(argc, argv, client_instance);
 #endif
 }

apps/desktop/src/gui/application/gui_application.cpp

@@ -2029,7 +2029,7 @@ void GuiApplication::ShareLocalCursorState() {
     if (!delivery.has_sent ||
         delivery.last_sent.render_mode != outgoing.render_mode ||
         delivery.last_sent.hidden_reason != outgoing.hidden_reason) {
-      LOG_INFO("Send cursor presentation to [{}]: mode={}, reason={}",
+      LOG_DEBUG("Send cursor presentation to [{}]: mode={}, reason={}",
                recipient.remote_id, static_cast<int>(outgoing.render_mode),
                static_cast<int>(outgoing.hidden_reason));
     }

apps/desktop/src/gui/features/devices/session_device_manager.cpp

@@ -82,7 +82,7 @@ void SessionDeviceManager::RecordCaptureCadence(
                            : capture_secure_callbacks_ == capture_callbacks_
                                ? "secure_desktop"
                                : "mixed";
-      LOG_INFO(
+      LOG_DEBUG(
           "Capture delivery: source={} normal_callbacks={} secure_callbacks={} "
           "target_fps={} input_fps={:.2f} "
           "forwarded_fps={:.2f} callbacks={} rate_dropped={} "
@@ -225,7 +225,7 @@ int SessionDeviceManager::InitializeScreenCapturer() {
                                     last_video_frame_stream_id_ != stream_id;
         if (resumed_after_gap || stream_changed) {
           if (RequestVideoKeyFrame(owner_.peer_, stream_id.c_str()) == 0) {
-            LOG_INFO("Request video key frame before sending captured frame, "
+            LOG_DEBUG("Request video key frame before sending captured frame, "
                      "stream='{}', gap_ms={}, stream_changed={}",
                      stream_id, duration_ms, stream_changed);
           }

apps/desktop/src/gui/runtime/peer_data_callbacks.cpp

@@ -294,7 +294,7 @@ void PeerEventHandler::OnReceiveDataBuffer(
       props->remote_cursor_state_received_ = true;
       props->cursor_presentation_.Observe(merged, SDL_GetTicks());
       if (changed) {
-        LOG_INFO("Received cursor state: seq={}, visible={}, shape={}, "
+        LOG_DEBUG("Received cursor state: seq={}, visible={}, shape={}, "
                  "mode={}, reason={}",
                  remote_action.cs.seq, remote_action.cs.visible,
                  static_cast<int>(remote_action.cs.shape),

apps/desktop/src/log/rd_log.cpp

@@ -1,11 +1,7 @@
 #include "rd_log.h"
 
-#include <chrono>
-#include <ctime>
 #include <filesystem>
-#include <iomanip>
 #include <mutex>
-#include <sstream>
 #include <vector>
 
 #include "spdlog/sinks/rotating_file_sink.h"
@@ -16,6 +12,7 @@ namespace crossdesk {
 namespace {
 
 std::string g_log_dir = "logs";
+std::string g_logger_name = LOGGER_NAME;
 std::once_flag g_logger_once_flag;
 std::mutex g_logger_mutex;
 std::shared_ptr<spdlog::logger> g_logger;
@@ -29,20 +26,20 @@ std::string NormalizeLogDirectory(const std::string& log_dir) {
 
 }  // namespace
 
-void InitLogger(const std::string& log_dir) {
+void InitLogger(const std::string& log_dir, const std::string& logger_name) {
   const auto directory = NormalizeLogDirectory(log_dir);
   std::lock_guard<std::mutex> lock(g_logger_mutex);
   if (g_logger) {
-    if (directory != g_log_dir) {
+    if (directory != g_log_dir || logger_name != g_logger_name) {
       g_logger->warn(
-          "InitLogger called after logger initialized. Ignoring log_dir: {}, "
-          "using previous log_dir: {}",
-          directory, g_log_dir);
+          "InitLogger called after logger initialized. Keeping logger {} in {}",
+          g_logger_name, g_log_dir);
     }
     return;
   }
 
   g_log_dir = directory;
+  g_logger_name = logger_name;
 }
 
 std::shared_ptr<spdlog::logger> get_logger() {
@@ -53,32 +50,23 @@ std::shared_ptr<spdlog::logger> get_logger() {
     std::error_code ec;
     std::filesystem::create_directories(g_log_dir, ec);
 
-    auto now = std::chrono::system_clock::now() + std::chrono::hours(8);
-    auto now_time = std::chrono::system_clock::to_time_t(now);
-
-    std::tm tm_info;
-#ifdef _WIN32
-    gmtime_s(&tm_info, &now_time);
-#else
-    gmtime_r(&now_time, &tm_info);
-#endif
-
-    std::stringstream ss;
-    ss << LOGGER_NAME;
-    ss << std::put_time(&tm_info, "-%Y%m%d-%H%M%S.log");
-
-    std::string filename = g_log_dir + "/" + ss.str();
+    // Reuse the same rotation set across restarts. Timestamped base names
+    // give each launch its own backups and let the directory grow forever.
+    auto file_sink = std::make_shared<spdlog::sinks::rotating_file_sink_mt>(
+        g_log_dir + "/" + g_logger_name + ".log", 5 * 1024 * 1024, 3);
 
     std::vector<spdlog::sink_ptr> sinks;
     sinks.push_back(std::make_shared<spdlog::sinks::stdout_color_sink_mt>());
-    sinks.push_back(std::make_shared<spdlog::sinks::rotating_file_sink_mt>(
-        filename, 5 * 1024 * 1024, 3));
+    sinks.push_back(file_sink);
 
-    auto logger = std::make_shared<spdlog::logger>(LOGGER_NAME, sinks.begin(),
+    auto logger = std::make_shared<spdlog::logger>(g_logger_name, sinks.begin(),
                                                    sinks.end());
+    logger->set_level(SPDLOG_ACTIVE_LEVEL <= SPDLOG_LEVEL_DEBUG
+                          ? spdlog::level::debug
+                          : spdlog::level::info);
     logger->flush_on(spdlog::level::info);
     spdlog::register_logger(logger);
-    logger->info("Logger initialized: path={}", filename);
+    logger->info("Logger initialized: path={}", file_sink->filename());
     g_logger = std::move(logger);
   });
 

apps/desktop/src/log/rd_log.h

@@ -10,21 +10,26 @@
 #include <memory>
 #include <string>
 
-#include "spdlog/spdlog.h"
-
+#ifndef SPDLOG_ACTIVE_LEVEL
 #define SPDLOG_ACTIVE_LEVEL SPDLOG_LEVEL_INFO
+#endif
+
+#include "spdlog/spdlog.h"
 
 namespace crossdesk {
 
 constexpr auto LOGGER_NAME = "crossdesk";
 
-void InitLogger(const std::string& log_dir);
+void InitLogger(const std::string& log_dir,
+                const std::string& logger_name = LOGGER_NAME);
 
 std::shared_ptr<spdlog::logger> get_logger();
 
+#define LOG_TRACE(...) SPDLOG_LOGGER_TRACE(get_logger(), __VA_ARGS__)
+#define LOG_DEBUG(...) SPDLOG_LOGGER_DEBUG(get_logger(), __VA_ARGS__)
 #define LOG_INFO(...) SPDLOG_LOGGER_INFO(get_logger(), __VA_ARGS__)
 #define LOG_WARN(...) SPDLOG_LOGGER_WARN(get_logger(), __VA_ARGS__)
 #define LOG_ERROR(...) SPDLOG_LOGGER_ERROR(get_logger(), __VA_ARGS__)
 #define LOG_FATAL(...) SPDLOG_LOGGER_CRITICAL(get_logger(), __VA_ARGS__)
 }  // namespace crossdesk
-#endif
+#endif

apps/desktop/src/platform/common/posix_single_instance.cpp

@@ -0,0 +1,68 @@
+#include "platform/single_instance.h"
+
+#include <cerrno>
+#include <cstring>
+#include <fcntl.h>
+#include <sys/file.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#include <utility>
+
+namespace crossdesk::platform {
+
+SingleInstanceGuard::SingleInstanceGuard(std::string application)
+    : application_(std::move(application)) {}
+
+SingleInstanceGuard::~SingleInstanceGuard() { Release(); }
+
+InstanceResult SingleInstanceGuard::TryAcquire(InstanceRole role,
+                                               std::string& error) {
+  error.clear();
+  if (handle_ != -1) return InstanceResult::kAcquired;
+  if (!ValidInstanceApplication(application_)) {
+    error = "Invalid single-instance application name";
+    return InstanceResult::kError;
+  }
+  // A fixed local path also coordinates launches with different TMPDIR/XDG
+  // settings. O_CLOEXEC prevents unrelated desktop/helper processes retaining it.
+  const std::string path = "/tmp/" + application_ + "-" +
+                           std::to_string(geteuid()) + "-" +
+                           InstanceRoleName(role) + ".lock";
+  const int fd = open(path.c_str(), O_CREAT | O_RDWR | O_CLOEXEC | O_NOFOLLOW, 0600);
+  if (fd < 0) {
+    error = "Cannot open single-instance lock: " + std::string(std::strerror(errno));
+    return InstanceResult::kError;
+  }
+  struct stat info {};
+  if (fstat(fd, &info) != 0 || !S_ISREG(info.st_mode) || info.st_uid != geteuid()) {
+    close(fd);
+    error = "Single-instance lock is not a regular file owned by this user";
+    return InstanceResult::kError;
+  }
+  int result;
+  do {
+    result = flock(fd, LOCK_EX | LOCK_NB);
+  } while (result != 0 && errno == EINTR);
+  if (result == 0) {
+    handle_ = fd;
+    return InstanceResult::kAcquired;
+  }
+  const int lock_error = errno;
+  close(fd);
+  if (lock_error == EWOULDBLOCK || lock_error == EAGAIN)
+    return InstanceResult::kAlreadyRunning;
+  error = "Cannot acquire single-instance lock: " +
+          std::string(std::strerror(lock_error));
+  return InstanceResult::kError;
+}
+
+void SingleInstanceGuard::Release() {
+  if (handle_ == -1) return;
+  // Close rather than LOCK_UN: a forked headless application may still own the
+  // same open file description. Never unlink a lock that another launch opened.
+  close(static_cast<int>(handle_));
+  handle_ = -1;
+}
+
+}  // namespace crossdesk::platform

apps/desktop/src/platform/linux/headless/headless_console.cpp

@@ -78,7 +78,7 @@ bool HeadlessConsole::Enable(const std::filesystem::path& log_directory,
   error_ = err;
   interactive_ = isatty(STDIN_FILENO) && isatty(output_);
   // Initialize after redirecting output so even the logger's first message
-  // stays in its original crossdesk-YYYYMMDD-HHMMSS.log file.
+  // stays in crossdesk.log.
   try {
     InitLogger(log_directory.string());
     for (const auto& sink : get_logger()->sinks()) {

apps/desktop/src/platform/single_instance.h

@@ -0,0 +1,53 @@
+/*
+ * @Author: DI JUNKUN
+ * @Date: 2026-09-26
+ * Copyright (c) 2026 by DI JUNKUN, All Rights Reserved.
+ */
+
+#ifndef _SINGLE_INSTANCE_H_
+#define _SINGLE_INSTANCE_H_
+
+#include <cstdint>
+#include <string>
+
+namespace crossdesk::platform {
+
+enum class InstanceRole { kLauncher, kClient, kServiceCli };
+enum class InstanceResult { kAcquired, kAlreadyRunning, kError };
+
+// Per-user ownership, independent of the install/portable directory. The OS
+// releases ownership on process exit, including crashes; no PID files to age out.
+class SingleInstanceGuard {
+ public:
+  explicit SingleInstanceGuard(std::string application = "CrossDesk");
+  ~SingleInstanceGuard();
+  SingleInstanceGuard(const SingleInstanceGuard&) = delete;
+  SingleInstanceGuard& operator=(const SingleInstanceGuard&) = delete;
+
+  InstanceResult TryAcquire(InstanceRole role, std::string& error);
+  void Release();
+
+ private:
+  std::string application_;
+  std::intptr_t handle_ = -1;
+};
+
+inline const char* InstanceRoleName(InstanceRole role) {
+  switch (role) {
+    case InstanceRole::kLauncher: return "launcher";
+    case InstanceRole::kClient: return "client";
+    case InstanceRole::kServiceCli: return "service-cli";
+  }
+  return "client";
+}
+
+inline bool ValidInstanceApplication(const std::string& application) {
+  return !application.empty() && application.size() <= 100 &&
+         application.find_first_not_of(
+             "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_") ==
+             std::string::npos;
+}
+
+}  // namespace crossdesk::platform
+
+#endif

apps/desktop/src/platform/windows/screen_capturer/screen_capturer_dxgi.cpp

@@ -547,7 +547,7 @@ void ScreenCapturerDxgi::CaptureLoop() {
       if (last_logged_cursor_embedding_ < 0 ||
           (software_cursor_output_ &&
            last_logged_cursor_embedding_ != static_cast<int>(cursor_embedded))) {
-        LOG_INFO("DXGI cursor: monitor={} usbmmidd={} mouse_update={} "
+        LOG_DEBUG("DXGI cursor: monitor={} usbmmidd={} mouse_update={} "
                  "separate_pointer_visible={} pointer_shape_bytes={} "
                  "compose_cursor={} embedded={}",
                  frame_monitor, software_cursor_output_,

apps/desktop/src/platform/windows/screen_capturer/screen_capturer_win.cpp

@@ -1638,7 +1638,7 @@ void ScreenCapturerWin::SecureDesktopCaptureLoop() {
     const ULONGLONG elapsed = GetTickCount64() - stats_started;
     if (elapsed == 0 || (!force && elapsed < 5000)) return;
     if (shared_frames || fallback_frames || shared_waits || shared_restarts) {
-      LOG_INFO(
+      LOG_DEBUG(
           "Secure capture delivery: shared_fps={:.1f}, fallback_fps={:.1f}, "
           "pending_waits={}, shared_restarts={}, status_max_ms={}",
           shared_frames * 1000.0 / elapsed, fallback_frames * 1000.0 / elapsed,

apps/desktop/src/platform/windows/screen_capturer/wgc_plugin_entry.cpp

@@ -12,7 +12,7 @@ void InitializePluginLogger() {
   static std::once_flag once;
   std::call_once(once, []() {
     crossdesk::PathManager path_manager("CrossDesk");
-    crossdesk::InitLogger(path_manager.GetLogPath().string());
+    crossdesk::InitLogger(path_manager.GetLogPath().string(), "crossdesk-wgc");
   });
 }
 

apps/desktop/src/platform/windows/single_instance.cpp

@@ -0,0 +1,71 @@
+#include "platform/single_instance.h"
+
+#include <windows.h>
+#include <sddl.h>
+
+#include <utility>
+#include <vector>
+
+namespace crossdesk::platform {
+
+SingleInstanceGuard::SingleInstanceGuard(std::string application)
+    : application_(std::move(application)) {}
+
+SingleInstanceGuard::~SingleInstanceGuard() { Release(); }
+
+InstanceResult SingleInstanceGuard::TryAcquire(InstanceRole role,
+                                               std::string& error) {
+  error.clear();
+  if (handle_ != -1) return InstanceResult::kAcquired;
+  if (!ValidInstanceApplication(application_)) {
+    error = "Invalid single-instance application name";
+    return InstanceResult::kError;
+  }
+  HANDLE token = nullptr;
+  if (!OpenProcessToken(GetCurrentProcess(), TOKEN_QUERY, &token)) {
+    error = "Cannot read current user token: " + std::to_string(GetLastError());
+    return InstanceResult::kError;
+  }
+  DWORD size = 0;
+  GetTokenInformation(token, TokenUser, nullptr, 0, &size);
+  std::vector<unsigned char> buffer(size);
+  if (!GetTokenInformation(token, TokenUser, buffer.data(), size, &size)) {
+    const DWORD code = GetLastError();
+    CloseHandle(token);
+    error = "Cannot read current user SID: " + std::to_string(code);
+    return InstanceResult::kError;
+  }
+  CloseHandle(token);
+  wchar_t* sid = nullptr;
+  if (!ConvertSidToStringSidW(reinterpret_cast<TOKEN_USER*>(buffer.data())->User.Sid,
+                             &sid)) {
+    error = "Cannot format current user SID: " + std::to_string(GetLastError());
+    return InstanceResult::kError;
+  }
+  const std::string role_name = InstanceRoleName(role);
+  const std::wstring name = L"Global\\" +
+      std::wstring(application_.begin(), application_.end()) + L"." + sid + L"." +
+      std::wstring(role_name.begin(), role_name.end());
+  LocalFree(sid);
+  // Object lifetime is the lease. No thread-owned mutex to transfer to a daemon.
+  HANDLE mutex = CreateMutexW(nullptr, FALSE, name.c_str());
+  const DWORD code = GetLastError();
+  if (!mutex) {
+    error = "Cannot create single-instance mutex: " + std::to_string(code);
+    return InstanceResult::kError;
+  }
+  if (code == ERROR_ALREADY_EXISTS) {
+    CloseHandle(mutex);
+    return InstanceResult::kAlreadyRunning;
+  }
+  handle_ = reinterpret_cast<std::intptr_t>(mutex);
+  return InstanceResult::kAcquired;
+}
+
+void SingleInstanceGuard::Release() {
+  if (handle_ == -1) return;
+  CloseHandle(reinterpret_cast<HANDLE>(handle_));
+  handle_ = -1;
+}
+
+}  // namespace crossdesk::platform

apps/desktop/xmake/options.lua

@@ -38,7 +38,9 @@ function setup_options_and_dependencies()
     add_defines("USE_WAYLAND=" .. (is_config("USE_WAYLAND", true) and "1" or "0"))
     add_defines("USE_DRM=" .. (is_config("USE_DRM", true) and "1" or "0"))
     if is_mode("debug") then
-        add_defines("CROSSDESK_DEBUG")
+        add_defines("CROSSDESK_DEBUG", "SPDLOG_ACTIVE_LEVEL=SPDLOG_LEVEL_DEBUG")
+    else
+        add_defines("SPDLOG_ACTIVE_LEVEL=SPDLOG_LEVEL_INFO")
     end
 
     add_requireconfs("**.python", {version = "3.12", override = true, configs = {pgo = false}})

apps/desktop/xmake/targets.lua

@@ -135,6 +135,16 @@ function setup_targets()
             "apps/desktop/src/gui/runtime")
         add_files("apps/desktop/tests/cursor_position_test.cpp")
 
+    target("single_instance")
+        set_kind("object")
+        add_includedirs("apps/desktop/src", {public = true})
+        if is_os("windows") then
+            add_files("apps/desktop/src/platform/windows/single_instance.cpp")
+            add_syslinks("Advapi32")
+        else
+            add_files("apps/desktop/src/platform/common/posix_single_instance.cpp")
+        end
+
     target("repository_structure_test")
         set_kind("binary")
         set_default(false)
@@ -540,7 +550,7 @@ function setup_targets()
 
     target("crossdesk")
         set_kind("binary")
-        add_deps("rd_log", "desktop_common", "gui")
+        add_deps("rd_log", "desktop_common", "gui", "single_instance")
         add_files("apps/desktop/src/app/*.cpp")
         add_includedirs("apps/desktop/src", "apps/desktop/src/app", {public = true})
         if is_os("windows") then