2 files changed, 12 insertions, 4 deletions

diff --git a/src/OSSupport/Socket.h b/src/OSSupport/Socket.h
index e4ec895cb..9ec8c1111 100644
--- a/src/OSSupport/Socket.h
+++ b/src/OSSupport/Socket.h
@@ -74,7 +74,7 @@ public:
 	inline static bool IsSocketError(int a_ReturnedValue)
 	{
 		#ifdef _WIN32
-			return (a_ReturnedValue == SOCKET_ERROR || a_ReturnedValue == 0);
+			return ((a_ReturnedValue == SOCKET_ERROR) || (a_ReturnedValue == 0));
 		#else
 			return (a_ReturnedValue <= 0);
 		#endif
diff --git a/src/OSSupport/SocketThreads.cpp b/src/OSSupport/SocketThreads.cpp
index 7a3ef4274..153d6ed1d 100644
--- a/src/OSSupport/SocketThreads.cpp
+++ b/src/OSSupport/SocketThreads.cpp
@@ -86,7 +86,8 @@ void cSocketThreads::RemoveClient(const cCallback * a_Client)
 		}
 	}  // for itr - m_Threads[]
 
-	ASSERT(!"Removing an unknown client");
+	// This client wasn't found.
+	// It's not an error, because it may have been removed by a different thread in the meantime.
 }
 
 
@@ -491,10 +492,17 @@ void cSocketThreads::cSocketThread::ReadFromSockets(fd_set * a_Read)
 				{
 					case sSlot::ssNormal:
 					{
-						// Notify the callback that the remote has closed the socket; keep the slot
-						m_Slots[i].m_Client->SocketClosed();
+						// Close the socket on our side:
 						m_Slots[i].m_State = sSlot::ssRemoteClosed;
 						m_Slots[i].m_Socket.CloseSocket();
+
+						// Notify the callback that the remote has closed the socket, *after* removing the socket:
+						cCallback * client = m_Slots[i].m_Client;
+						m_Slots[i] = m_Slots[--m_NumSlots];
+						if (client != nullptr)
+						{
+							client->SocketClosed();
+						}
 						break;
 					}
 					case sSlot::ssWritingRestOut: