I have run sample message loops which does both send and receive messages for about 12 hours on IE and Chrome using longPolling transport, the results for process memory data Working Set –Private show that there are memory leaks.

BTW, the run for directly using XMLHttpRequest to send message /post and poll/get to signalr ( just like longPolling ) in infinite loops but without SignalR js run for over 10 hours on Chrome, doesn’t show memory leaks.