diff --git a/proxy/tg_ws_proxy.py b/proxy/tg_ws_proxy.py
index c3c00c6..b6d853e 100644
--- a/proxy/tg_ws_proxy.py
+++ b/proxy/tg_ws_proxy.py
@@ -596,7 +596,7 @@ async def _handle_client(reader, writer):
                 rr, rw = await asyncio.wait_for(
                     asyncio.open_connection(dst, port), timeout=10)
             except Exception as exc:
-                log.warning("[%s] passthrough failed to %s: %s", label, dst, exc)
+                log.warning("[%s] passthrough failed to %s: %s: %s", label, dst, type(exc).__name__, str(exc) or "(no message)")
                 writer.write(_socks5_reply(0x05))
                 await writer.drain()
                 writer.close()
diff --git a/requirements-win7.txt b/requirements-win7.txt
index 491d3f5..41a8174 100644
--- a/requirements-win7.txt
+++ b/requirements-win7.txt
@@ -3,3 +3,4 @@ customtkinter==5.2.2
 Pillow==10.4.0
 psutil==5.9.8
 pystray==0.19.5
+pyperclip==1.9.0
diff --git a/requirements.txt b/requirements.txt
index ba9706d..c7a85f3 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -3,3 +3,4 @@ customtkinter==5.2.2
 Pillow==12.1.1
 psutil==7.0.0
 pystray==0.19.5
+pyperclip==1.9.0
diff --git a/windows.py b/windows.py
index bd8d25f..e0bd25f 100644
--- a/windows.py
+++ b/windows.py
@@ -10,6 +10,7 @@ import threading
 import time
 import webbrowser
 import pystray
+import pyperclip
 import asyncio as _asyncio
 import customtkinter as ctk
 from pathlib import Path
@@ -42,13 +43,27 @@ _exiting: bool = False
 log = logging.getLogger("tg-ws-tray")
 
 
-def is_already_running():
-    current_proc = os.path.basename(sys.argv[0])
-    count = 0
-    for process in psutil.process_iter(['name']):
-        if process.info['name'] == current_proc:
-            count += 1
-    return count > 2
+def _acquire_lock() -> bool:
+    _ensure_dirs()
+    lock_files = list(APP_DIR.glob("*.lock"))
+        
+    for f in lock_files:
+        try:
+            pid = int(f.stem)
+            if psutil.pid_exists(pid):
+                try:
+                    psutil.Process(pid).status()
+                    return False
+                except (psutil.NoSuchProcess, psutil.ZombieProcess):
+                    pass
+        except Exception:
+            pass
+
+        f.unlink(missing_ok=True)
+
+    lock_file = APP_DIR / f"{os.getpid()}.lock"
+    lock_file.touch()
+    return True
 
 
 def _ensure_dirs():
@@ -148,6 +163,8 @@ def _run_proxy_thread(port: int, dc_opt: Dict[int, str], verbose: bool):
             tg_ws_proxy._run(port, dc_opt, stop_event=stop_ev))
     except Exception as exc:
         log.error("Proxy thread crashed: %s", exc)
+        if "10048" in str(exc) or "Address already in use" in str(exc):
+            _show_error("Не удалось запустить прокси:\nПорт уже используется другим приложением.\n\nЗакройте приложение, использующее этот порт, или измените порт в настройках прокси и перезапустите.")
     finally:
         loop.close()
         _async_stop = None
@@ -216,7 +233,7 @@ def _on_open_in_telegram(icon=None, item=None):
     except Exception:
         log.info("Browser open failed, copying to clipboard")
         try:
-            _copy_to_clipboard(url)
+            pyperclip.copy(url)
             _show_info(
                 f"Не удалось открыть Telegram автоматически.\n\n"
                 f"Ссылка скопирована в буфер обмена, отправьте её в телеграмм и нажмите по ней ЛКМ:\n{url}",
@@ -226,31 +243,11 @@ def _on_open_in_telegram(icon=None, item=None):
             _show_error(f"Не удалось скопировать ссылку:\n{exc}")
 
 
-def _copy_to_clipboard(text: str):
-    """Copy text to Windows clipboard using ctypes."""
-    import ctypes.wintypes
-    CF_UNICODETEXT = 13
-    kernel32 = ctypes.windll.kernel32
-    user32 = ctypes.windll.user32
-
-    user32.OpenClipboard(0)
-    user32.EmptyClipboard()
-
-    encoded = text.encode("utf-16-le") + b"\x00\x00"
-    h = kernel32.GlobalAlloc(0x0042, len(encoded))  # GMEM_MOVEABLE | GMEM_ZEROINIT
-    p = kernel32.GlobalLock(h)
-    ctypes.memmove(p, encoded, len(encoded))
-    kernel32.GlobalUnlock(h)
-    user32.SetClipboardData(CF_UNICODETEXT, h)
-    user32.CloseClipboard()
-
-
 def _on_restart(icon=None, item=None):
     threading.Thread(target=restart_proxy, daemon=True).start()
 
 
 def _on_edit_config(icon=None, item=None):
-    """Open a simple dialog to edit config."""
     threading.Thread(target=_edit_config_dialog, daemon=True).start()
 
 
@@ -571,7 +568,7 @@ def run_tray():
 
 
 def main():
-    if is_already_running():
+    if not _acquire_lock():
         _show_info("Приложение уже запущено.", os.path.basename(sys.argv[0]))
         return