diff --git a/Chat/Client/Singleton.cs b/Chat/Client/Singleton.cs
index b6fbbe5..98a6e22 100644
--- a/Chat/Client/Singleton.cs
+++ b/Chat/Client/Singleton.cs
@@ -44,69 +44,78 @@ namespace Client
 
 			Socket socket = (Socket)sender;
 			byte[] headerBuffer = new byte[2];
-			while (true)
+
+			try
 			{
-				// header buffer
-				int n1 = await socket.ReceiveAsync(headerBuffer, SocketFlags.None);
-				if (n1 < 1)
-				{
-					Console.WriteLine($"[{DateTime.Now}] Disconnect server: {socket.RemoteEndPoint}");
-					socket.Dispose();
-					return;
-				}
-				else if (n1 == 1)
+				while (true)
 				{
-					await socket.ReceiveAsync(new ArraySegment<byte>(headerBuffer, 1, 1), SocketFlags.None);
-				}
+					// header buffer
+					int n1 = await socket.ReceiveAsync(headerBuffer, SocketFlags.None);
+					if (n1 < 1)
+					{
+						Console.WriteLine($"[{DateTime.Now}] Disconnect server: {socket.RemoteEndPoint}");
+						socket.Dispose();
+						return;
+					}
+					else if (n1 == 1)
+					{
+						await socket.ReceiveAsync(new ArraySegment<byte>(headerBuffer, 1, 1), SocketFlags.None);
+					}
 
-				// data buffer
-				short dataSize = IPAddress.NetworkToHostOrder(BitConverter.ToInt16(headerBuffer));
-				byte[] dataBuffer = new byte[dataSize];
+					// data buffer
+					short dataSize = IPAddress.NetworkToHostOrder(BitConverter.ToInt16(headerBuffer));
+					byte[] dataBuffer = new byte[dataSize];
 
-				int totalRecv = 0;
-				while (totalRecv < dataSize)
-				{
-					int n2 = await socket.ReceiveAsync(new ArraySegment<byte>(dataBuffer, totalRecv, dataSize - totalRecv), SocketFlags.None);
-					totalRecv += n2;
-				}
+					int totalRecv = 0;
+					while (totalRecv < dataSize)
+					{
+						int n2 = await socket.ReceiveAsync(new ArraySegment<byte>(dataBuffer, totalRecv, dataSize - totalRecv), SocketFlags.None);
+						totalRecv += n2;
+					}
 
-				PacketType packetType = (PacketType)IPAddress.NetworkToHostOrder(BitConverter.ToInt16(dataBuffer));
-				if (packetType == PacketType.LoginResponse)
-				{
-					LoginResponsePacket packet = new LoginResponsePacket(dataBuffer);
-					LoginResponsed?.Invoke(packet, EventArgs.Empty);
-				}
-				else if (packetType == PacketType.CreateRoomResponse)
-				{
-					CreateRoomResponsePacket packet = new CreateRoomResponsePacket(dataBuffer);
-					CreateRoomResponsed?.Invoke(packet, EventArgs.Empty);
-				}
-				else if (packetType == PacketType.RoomListResponse)
-				{
-					RoomListResponsePacket packet = new RoomListResponsePacket(dataBuffer);
-					RoomListResponsed?.Invoke(packet, EventArgs.Empty);
-				}
-				else if (packetType == PacketType.EnterRoomResponse)
-				{
-					EnterRoomResponsePacket packet = new EnterRoomResponsePacket(dataBuffer);
-					EnterRoomResponsed?.Invoke(packet, EventArgs.Empty);
-				}
-				else if (packetType == PacketType.UserEnter)
-				{
-					UserEnterPacket packet = new UserEnterPacket(dataBuffer);
-					UserEnterResponsed?.Invoke(packet, EventArgs.Empty);
-				}
-				else if (packetType == PacketType.UserLeave)
-				{
-					UserLeavePacket packet = new UserLeavePacket(dataBuffer);
-					UserLeaveResponsed?.Invoke(packet, EventArgs.Empty);
-				}
-				else if (packetType == PacketType.Chat)
-				{
-					ChatPacket packet = new ChatPacket(dataBuffer);
-					ChatResponsed?.Invoke(packet, EventArgs.Empty);
+					PacketType packetType = (PacketType)IPAddress.NetworkToHostOrder(BitConverter.ToInt16(dataBuffer));
+					if (packetType == PacketType.LoginResponse)
+					{
+						LoginResponsePacket packet = new LoginResponsePacket(dataBuffer);
+						LoginResponsed?.Invoke(packet, EventArgs.Empty);
+					}
+					else if (packetType == PacketType.CreateRoomResponse)
+					{
+						CreateRoomResponsePacket packet = new CreateRoomResponsePacket(dataBuffer);
+						CreateRoomResponsed?.Invoke(packet, EventArgs.Empty);
+					}
+					else if (packetType == PacketType.RoomListResponse)
+					{
+						RoomListResponsePacket packet = new RoomListResponsePacket(dataBuffer);
+						RoomListResponsed?.Invoke(packet, EventArgs.Empty);
+					}
+					else if (packetType == PacketType.EnterRoomResponse)
+					{
+						EnterRoomResponsePacket packet = new EnterRoomResponsePacket(dataBuffer);
+						EnterRoomResponsed?.Invoke(packet, EventArgs.Empty);
+					}
+					else if (packetType == PacketType.UserEnter)
+					{
+						UserEnterPacket packet = new UserEnterPacket(dataBuffer);
+						UserEnterResponsed?.Invoke(packet, EventArgs.Empty);
+					}
+					else if (packetType == PacketType.UserLeave)
+					{
+						UserLeavePacket packet = new UserLeavePacket(dataBuffer);
+						UserLeaveResponsed?.Invoke(packet, EventArgs.Empty);
+					}
+					else if (packetType == PacketType.Chat)
+					{
+						ChatPacket packet = new ChatPacket(dataBuffer);
+						ChatResponsed?.Invoke(packet, EventArgs.Empty);
+					}
 				}
 			}
+			catch (Exception ex)
+			{
+				MessageBox.Show(ex.ToString());
+				Environment.Exit(1);
+			}
 		}
 	}
 }
diff --git a/Chat/Core/PServer.cs b/Chat/Core/PServer.cs
index 1c046b6..b617926 100644
--- a/Chat/Core/PServer.cs
+++ b/Chat/Core/PServer.cs
@@ -27,9 +27,16 @@ namespace Core
 		{
 			while (true)
 			{
-				Socket clientSocket = await serverSocket.AcceptAsync();
-				Console.WriteLine($"[{DateTime.Now}] Accept client: {clientSocket.RemoteEndPoint}");
-				ThreadPool.QueueUserWorkItem(RunAsync, clientSocket);
+				try
+				{
+					Socket clientSocket = await serverSocket.AcceptAsync();
+					Console.WriteLine($"[{DateTime.Now}] Accept client: {clientSocket.RemoteEndPoint}");
+					ThreadPool.QueueUserWorkItem(RunAsync, clientSocket);
+				}
+				catch (Exception ex)
+				{
+					Console.WriteLine(ex);
+				}
 			}
 		}
 
@@ -45,143 +52,175 @@ namespace Core
 			string nickname = "";
 			string roomName = "";
 
-			while (true)
+			try
 			{
-				// header buffer
-				int n1 = await clientSocket.ReceiveAsync(headerBuffer, SocketFlags.None);
-				if (n1 < 1)
+				while (true)
 				{
-					Console.WriteLine($"[{DateTime.Now}] Disconnect client - {clientSocket.RemoteEndPoint}");
-					clientSocket.Dispose();
-					return;
-				}
-				else if (n1 == 1)
-				{
-					await clientSocket.ReceiveAsync(new ArraySegment<byte>(headerBuffer, 1, 1), SocketFlags.None);
-				}
+					// header buffer
+					int n1 = await clientSocket.ReceiveAsync(headerBuffer, SocketFlags.None);
+					if (n1 < 1)
+					{
+						Console.WriteLine($"[{DateTime.Now}] Disconnect client - {clientSocket.RemoteEndPoint}");
+						await Remove(id, nickname, roomName, clientSocket);
+						return;
+					}
+					else if (n1 == 1)
+					{
+						await clientSocket.ReceiveAsync(new ArraySegment<byte>(headerBuffer, 1, 1), SocketFlags.None);
+					}
 
-				// data buffer
-				short dataSize = IPAddress.NetworkToHostOrder(BitConverter.ToInt16(headerBuffer));
-				byte[] dataBuffer = new byte[dataSize];
+					// data buffer
+					short dataSize = IPAddress.NetworkToHostOrder(BitConverter.ToInt16(headerBuffer));
+					byte[] dataBuffer = new byte[dataSize];
 
-				int totalRecv = 0;
-				while (totalRecv < dataSize)
-				{
-					int n2 = await clientSocket.ReceiveAsync(new ArraySegment<byte>(dataBuffer, totalRecv, dataSize - totalRecv), SocketFlags.None);
-					totalRecv += n2;
-				}
+					int totalRecv = 0;
+					while (totalRecv < dataSize)
+					{
+						int n2 = await clientSocket.ReceiveAsync(new ArraySegment<byte>(dataBuffer, totalRecv, dataSize - totalRecv), SocketFlags.None);
+						totalRecv += n2;
+					}
 
-				PacketType packetType = (PacketType)IPAddress.NetworkToHostOrder(BitConverter.ToInt16(dataBuffer));
-				if (packetType == PacketType.LoginRequest)
-				{
-					LoginRequestPacket requestPacket = new LoginRequestPacket(dataBuffer);
-					
-					bool result = Clients.TryAdd(requestPacket.Id, clientSocket);
-					Console.WriteLine($"[{DateTime.Now}] LoginRequest - Id: {requestPacket.Id}, Nickname: {requestPacket.NickName}");
+					PacketType packetType = (PacketType)IPAddress.NetworkToHostOrder(BitConverter.ToInt16(dataBuffer));
+					if (packetType == PacketType.LoginRequest)
+					{
+						LoginRequestPacket requestPacket = new LoginRequestPacket(dataBuffer);
 
-					id = requestPacket.Id;
-					nickname = requestPacket.NickName;
+						bool result = Clients.TryAdd(requestPacket.Id, clientSocket);
+						Console.WriteLine($"[{DateTime.Now}] LoginRequest - Id: {requestPacket.Id}, Nickname: {requestPacket.NickName}");
 
-					LoginResponsePacket responsePacket = new LoginResponsePacket(result ? StatusCode.Success : StatusCode.Failed);
-					await clientSocket.SendAsync(responsePacket.Serialize(), SocketFlags.None);
-				}
-				else if (packetType == PacketType.CreateRoomRequest)
-				{
-					CreateRoomRequestPacket requestPacket = new CreateRoomRequestPacket(dataBuffer);
-					Room room = new Room();
-					if (Rooms.TryAdd(requestPacket.RoomName, room))
-					{
-						roomName = requestPacket.RoomName;
-						room.Users.TryAdd(id, nickname);
-						Console.WriteLine($"[{DateTime.Now}] CreateRoomRequest - RoomName: {roomName}, id: {id}, nickname: {nickname}");
+						id = requestPacket.Id;
+						nickname = requestPacket.NickName;
 
-						CreateRoomResponsePacket responsePacket = new CreateRoomResponsePacket(StatusCode.Success);
+						LoginResponsePacket responsePacket = new LoginResponsePacket(result ? StatusCode.Success : StatusCode.Failed);
 						await clientSocket.SendAsync(responsePacket.Serialize(), SocketFlags.None);
 					}
-					else
+					else if (packetType == PacketType.CreateRoomRequest)
 					{
-						Console.WriteLine($"[{DateTime.Now}] CreateRoomRequest failed - RoomName: {requestPacket.RoomName}");
+						CreateRoomRequestPacket requestPacket = new CreateRoomRequestPacket(dataBuffer);
+						Room room = new Room();
+						if (Rooms.TryAdd(requestPacket.RoomName, room))
+						{
+							roomName = requestPacket.RoomName;
+							room.Users.TryAdd(id, nickname);
+							Console.WriteLine($"[{DateTime.Now}] CreateRoomRequest - RoomName: {roomName}, id: {id}, nickname: {nickname}");
 
-						CreateRoomResponsePacket responsePacket = new CreateRoomResponsePacket(StatusCode.Failed);
-						await clientSocket.SendAsync(responsePacket.Serialize(), SocketFlags.None);
+							CreateRoomResponsePacket responsePacket = new CreateRoomResponsePacket(StatusCode.Success);
+							await clientSocket.SendAsync(responsePacket.Serialize(), SocketFlags.None);
+						}
+						else
+						{
+							Console.WriteLine($"[{DateTime.Now}] CreateRoomRequest failed - RoomName: {requestPacket.RoomName}");
+
+							CreateRoomResponsePacket responsePacket = new CreateRoomResponsePacket(StatusCode.Failed);
+							await clientSocket.SendAsync(responsePacket.Serialize(), SocketFlags.None);
+						}
 					}
-				}
-				else if (packetType == PacketType.RoomListRequest)
-				{
-					RoomListResponsePacket packet = new RoomListResponsePacket(Rooms.Keys);
-					await clientSocket.SendAsync(packet.Serialize(), SocketFlags.None);
-				}
-				else if (packetType == PacketType.EnterRoomRequest)
-				{
-					EnterRoomRequestPacket requestPacket = new EnterRoomRequestPacket(dataBuffer);
-					if (Rooms.TryGetValue(requestPacket.RoomName, out var room))
+					else if (packetType == PacketType.RoomListRequest)
 					{
-						roomName = requestPacket.RoomName;
-						room.Users.TryAdd(id, nickname);
-						Console.WriteLine($"[{DateTime.Now}] EnterRoomRequest - RoomName: {roomName}, id: {id}, nickname: {nickname}");
-
-						EnterRoomResponsePacket responsePacket = new EnterRoomResponsePacket(StatusCode.Success);
-						await clientSocket.SendAsync(responsePacket.Serialize(), SocketFlags.None);
-
-						await Task.Delay(100);
-						foreach (var user in room.Users)
+						RoomListResponsePacket packet = new RoomListResponsePacket(Rooms.Keys);
+						await clientSocket.SendAsync(packet.Serialize(), SocketFlags.None);
+					}
+					else if (packetType == PacketType.EnterRoomRequest)
+					{
+						EnterRoomRequestPacket requestPacket = new EnterRoomRequestPacket(dataBuffer);
+						if (Rooms.TryGetValue(requestPacket.RoomName, out var room))
 						{
-							if (user.Value == nickname)
-								continue;
+							roomName = requestPacket.RoomName;
+							room.Users.TryAdd(id, nickname);
+							Console.WriteLine($"[{DateTime.Now}] EnterRoomRequest - RoomName: {roomName}, id: {id}, nickname: {nickname}");
+
+							EnterRoomResponsePacket responsePacket = new EnterRoomResponsePacket(StatusCode.Success);
+							await clientSocket.SendAsync(responsePacket.Serialize(), SocketFlags.None);
 
-							// add me to other user
-							if (Clients.TryGetValue(user.Key, out var otherClient))
+							await Task.Delay(100);
+							foreach (var user in room.Users)
 							{
-								UserEnterPacket enterPacket = new UserEnterPacket(nickname);
-								await otherClient.SendAsync(enterPacket.Serialize(), SocketFlags.None);
+								if (user.Value == nickname)
+									continue;
+
+								// add me to other user
+								if (Clients.TryGetValue(user.Key, out var otherClient))
+								{
+									UserEnterPacket enterPacket = new UserEnterPacket(nickname);
+									await otherClient.SendAsync(enterPacket.Serialize(), SocketFlags.None);
+								}
+
+								// add other user to me
+								UserEnterPacket packet = new UserEnterPacket(user.Value);
+								await clientSocket.SendAsync(packet.Serialize(), SocketFlags.None);
 							}
-
-							// add other user to me
-							UserEnterPacket packet = new UserEnterPacket(user.Value);
-							await clientSocket.SendAsync(packet.Serialize(), SocketFlags.None);
 						}
-					}
-					else
-					{
-						Console.WriteLine($"[{DateTime.Now}] EnterRoomRequest failed - RoomName: {requestPacket.RoomName}");
+						else
+						{
+							Console.WriteLine($"[{DateTime.Now}] EnterRoomRequest failed - RoomName: {requestPacket.RoomName}");
 
-						EnterRoomResponsePacket responsePacket = new EnterRoomResponsePacket(StatusCode.Failed);
-						await clientSocket.SendAsync(responsePacket.Serialize(), SocketFlags.None);
+							EnterRoomResponsePacket responsePacket = new EnterRoomResponsePacket(StatusCode.Failed);
+							await clientSocket.SendAsync(responsePacket.Serialize(), SocketFlags.None);
 
+						}
 					}
-				}
-				else if (packetType == PacketType.UserLeave)
-				{
-					UserLeavePacket packet = new UserLeavePacket(dataBuffer);
-					if (Rooms.TryGetValue(roomName, out var room))
+					else if (packetType == PacketType.UserLeave)
 					{
-						room.Users.TryRemove(id, out _);
+						UserLeavePacket packet = new UserLeavePacket(dataBuffer);
+						if (Rooms.TryGetValue(roomName, out var room))
+						{
+							room.Users.TryRemove(id, out _);
 
-						if (room.Users.IsEmpty)
-							Rooms.TryRemove(roomName, out _);
+							if (room.Users.IsEmpty)
+								Rooms.TryRemove(roomName, out _);
 
-						roomName = "";
+							roomName = "";
 
-						foreach (var user in room.Users)
-						{
-							if (Clients.TryGetValue(user.Key, out var otherClient))
-								await otherClient.SendAsync(packet.Serialize(), SocketFlags.None);
+							foreach (var user in room.Users)
+							{
+								if (Clients.TryGetValue(user.Key, out var otherClient))
+									await otherClient.SendAsync(packet.Serialize(), SocketFlags.None);
+							}
 						}
 					}
-				}
-				else if (packetType == PacketType.Chat)
-				{
-					ChatPacket packet = new ChatPacket(dataBuffer);
-					if (Rooms.TryGetValue(roomName, out var room))
+					else if (packetType == PacketType.Chat)
 					{
-						foreach (var user in room.Users)
+						ChatPacket packet = new ChatPacket(dataBuffer);
+						if (Rooms.TryGetValue(roomName, out var room))
 						{
-							if (Clients.TryGetValue(user.Key, out var otherClient))
-								await otherClient.SendAsync(packet.Serialize(), SocketFlags.None);
+							foreach (var user in room.Users)
+							{
+								if (Clients.TryGetValue(user.Key, out var otherClient))
+									await otherClient.SendAsync(packet.Serialize(), SocketFlags.None);
+							}
 						}
 					}
 				}
 			}
+			catch (Exception ex)
+			{
+				Console.WriteLine(ex);
+				await Remove(id, nickname, roomName, clientSocket);
+			}
+		}
+
+		private async Task Remove(string id, string nickname, string roomName, Socket clientSocket)
+		{
+			Clients.TryRemove(id, out _);
+			if (Rooms.TryGetValue(roomName, out var room))
+			{
+				UserLeavePacket packet = new UserLeavePacket(nickname);
+
+				room.Users.TryRemove(id, out _);
+
+				if (room.Users.IsEmpty)
+					Rooms.TryRemove(roomName, out _);
+
+				roomName = "";
+
+				foreach (var user in room.Users)
+				{
+					if (Clients.TryGetValue(user.Key, out var otherClient))
+						await otherClient.SendAsync(packet.Serialize(), SocketFlags.None);
+				}
+			}
+
+			clientSocket.Dispose();
 		}
 	}
 }