diff --git a/ErgometerApplication/ErgometerApplication/MainClient.cs b/ErgometerApplication/ErgometerApplication/MainClient.cs
index 8e48c7b..635b9a8 100644
--- a/ErgometerApplication/ErgometerApplication/MainClient.cs
+++ b/ErgometerApplication/ErgometerApplication/MainClient.cs
@@ -141,7 +141,7 @@ namespace ErgometerApplication
                     throw new Exception("Comport was unable to disconnect");
             }
 
-            if (Doctor.Connected)
+            if (Doctor != null && Doctor.Connected)
             {
                 NetHelper.SendNetCommand(Doctor, new NetCommand(NetCommand.CommandType.LOGOUT, Session));
                 Loggedin = false;
@@ -185,7 +185,8 @@ namespace ErgometerApplication
                 }
             }
 
-            Doctor.Close();
+            if(Doctor != null)
+                Doctor.Close();
         }
 
         private static void ParseCommand(NetCommand command)
diff --git a/ErgometerApplication/ErgometerApplication/bin/Debug/ErgometerLibrary.dll b/ErgometerApplication/ErgometerApplication/bin/Debug/ErgometerLibrary.dll
index 928d6ca..817a1db 100644
Binary files a/ErgometerApplication/ErgometerApplication/bin/Debug/ErgometerLibrary.dll and b/ErgometerApplication/ErgometerApplication/bin/Debug/ErgometerLibrary.dll differ