diff --git a/CHANGES b/CHANGES
index 4c57bf68..b84ed21e 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,7 @@
+2.0.11 2014-11-23
+- Fix a crash
+- Only switch the system proxy off if we have switched it on
+
 2.0.10 2014-11-18
 - Minor fixes
 - Optimize code
diff --git a/shadowsocks-csharp/Controller/Local.cs b/shadowsocks-csharp/Controller/Local.cs
index 97f21474..15649b40 100755
--- a/shadowsocks-csharp/Controller/Local.cs
+++ b/shadowsocks-csharp/Controller/Local.cs
@@ -144,7 +144,7 @@ namespace Shadowsocks.Controller
             }
             catch (Exception e)
             {
-                Console.WriteLine(e);
+                Logging.LogUsefulException(e);
                 this.Close();
             }
         }
@@ -176,7 +176,7 @@ namespace Shadowsocks.Controller
                 }
                 catch (Exception e)
                 {
-                    Console.WriteLine(e);
+                    Logging.LogUsefulException(e);
                 }
             }
             if (remote != null)
@@ -188,7 +188,7 @@ namespace Shadowsocks.Controller
                 }
                 catch (SocketException e)
                 {
-                    Console.WriteLine(e);
+                    Logging.LogUsefulException(e);
                 }
             }
             lock (encryptionLock)
@@ -218,7 +218,7 @@ namespace Shadowsocks.Controller
             }
             catch (Exception e)
             {
-                Console.WriteLine(e);
+                Logging.LogUsefulException(e);
                 this.Close();
             }
         }
@@ -236,7 +236,7 @@ namespace Shadowsocks.Controller
             }
             catch (Exception e)
             {
-                Console.WriteLine(e);
+                Logging.LogUsefulException(e);
                 this.Close();
             }
         }
@@ -269,7 +269,7 @@ namespace Shadowsocks.Controller
             }
             catch (Exception e)
             {
-                Console.WriteLine(e);
+                Logging.LogUsefulException(e);
                 this.Close();
             }
         }
@@ -296,7 +296,7 @@ namespace Shadowsocks.Controller
             }
             catch (Exception e)
             {
-                Console.WriteLine(e);
+                Logging.LogUsefulException(e);
                 this.Close();
             }
         }
@@ -324,7 +324,7 @@ namespace Shadowsocks.Controller
             }
             catch (Exception e)
             {
-                Console.WriteLine(e);
+                Logging.LogUsefulException(e);
                 this.Close();
             }
         }
@@ -346,7 +346,7 @@ namespace Shadowsocks.Controller
             }
             catch (Exception e)
             {
-                Console.WriteLine(e);
+                Logging.LogUsefulException(e);
                 this.Close();
             }
         }
@@ -384,7 +384,7 @@ namespace Shadowsocks.Controller
             }
             catch (Exception e)
             {
-                Console.WriteLine(e);
+                Logging.LogUsefulException(e);
                 this.Close();
             }
         }
@@ -421,7 +421,7 @@ namespace Shadowsocks.Controller
             }
             catch (Exception e)
             {
-                Console.WriteLine(e);
+                Logging.LogUsefulException(e);
                 this.Close();
             }
         }
@@ -440,7 +440,7 @@ namespace Shadowsocks.Controller
             }
             catch (Exception e)
             {
-                Console.WriteLine(e);
+                Logging.LogUsefulException(e);
                 this.Close();
             }
         }
@@ -459,7 +459,7 @@ namespace Shadowsocks.Controller
             }
             catch (Exception e)
             {
-                Console.WriteLine(e);
+                Logging.LogUsefulException(e);
                 this.Close();
             }
         }
diff --git a/shadowsocks-csharp/Controller/Logging.cs b/shadowsocks-csharp/Controller/Logging.cs
index 58a994f5..ada32ce5 100755
--- a/shadowsocks-csharp/Controller/Logging.cs
+++ b/shadowsocks-csharp/Controller/Logging.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
+using System.Net.Sockets;
 using System.Text;
 
 namespace Shadowsocks.Controller
@@ -30,5 +31,31 @@ namespace Shadowsocks.Controller
                 return false;
             }
         }
+
+        public static void LogUsefulException(Exception e)
+        {
+            // just log useful exceptions, not all of them
+            if (e is SocketException)
+            {
+                SocketException se = (SocketException)e;
+                if (se.SocketErrorCode == SocketError.ConnectionAborted)
+                {
+                    // closed by browser when sending
+                    // normally happens when download is canceled or a tab is closed before page is loaded
+                }
+                else if (se.SocketErrorCode == SocketError.ConnectionReset)
+                {
+                    // received rst
+                }
+                else
+                {
+                    Console.WriteLine(e);
+                }
+            }
+            else
+            {
+                Console.WriteLine(e);
+            }
+        }
     }
 }
diff --git a/shadowsocks-csharp/Controller/PACServer.cs b/shadowsocks-csharp/Controller/PACServer.cs
index 7b39252d..6e611b2b 100755
--- a/shadowsocks-csharp/Controller/PACServer.cs
+++ b/shadowsocks-csharp/Controller/PACServer.cs
@@ -174,7 +174,12 @@ Connection: Close
         private void SendCallback(IAsyncResult ar)
         {
             Socket conn = (Socket)ar.AsyncState;
-            conn.Shutdown(SocketShutdown.Send);
+            try
+            {
+                conn.Shutdown(SocketShutdown.Send);
+            }
+            catch
+            { }
         }
 
         private void WatchPacFile()
diff --git a/shadowsocks-csharp/Controller/ShadowsocksController.cs b/shadowsocks-csharp/Controller/ShadowsocksController.cs
index b4de4cf9..f5bdb44c 100755
--- a/shadowsocks-csharp/Controller/ShadowsocksController.cs
+++ b/shadowsocks-csharp/Controller/ShadowsocksController.cs
@@ -22,6 +22,8 @@ namespace Shadowsocks.Controller
         private PolipoRunner polipoRunner;
         private bool stopped = false;
 
+        private bool _systemProxyIsDirty = false;
+
         public class PathEventArgs : EventArgs
         {
             public string Path;
@@ -174,10 +176,16 @@ namespace Shadowsocks.Controller
             if (_config.enabled)
             {
                 SystemProxy.Enable();
+                _systemProxyIsDirty = true;
             }
             else
             {
-                SystemProxy.Disable();
+                // only switch it off if we have switched it on
+                if (_systemProxyIsDirty)
+                {
+                    SystemProxy.Disable();
+                    _systemProxyIsDirty = false;
+                }
             }
         }
 
diff --git a/shadowsocks-csharp/Properties/AssemblyInfo.cs b/shadowsocks-csharp/Properties/AssemblyInfo.cs
index e65ce0b3..47f94a5e 100755
--- a/shadowsocks-csharp/Properties/AssemblyInfo.cs
+++ b/shadowsocks-csharp/Properties/AssemblyInfo.cs
@@ -32,5 +32,5 @@ using System.Runtime.InteropServices;
 // 可以指定所有这些值，也可以使用“内部版本号”和“修订号”的默认值，
 // 方法是按如下所示使用“*”:
 // [assembly: AssemblyVersion("1.0.*")]
-[assembly: AssemblyVersion("2.0.10")]
+[assembly: AssemblyVersion("2.0.11")]
 // [assembly: AssemblyFileVersion("2.0.0")]