Hi All, I an working with Visual Studio C++ 2005 V 2.0.50727 and pjproject-1.0 sources I implement pjsua to play a couple of wav-files simultainiously to a couple of sip-phones. The wave-files can be changed from a Windows dialog during the call. A button in the dialog initiates a call. The PJSIP_INV_STATE_CONFIRMED sends a user defined message to the dialog (SendMessage funcuntion), and wav-player with eof-callback hook is created and connected to the port. The player-eof callback disconnect and destroys the player, and uses SendMessage to signal to the dialog, which now plays the next file. Everything works fine for about 10 minutes on 2 lines. After 10 minutes and faster with more lines I encounter a deadlock after: pjsua_call.c Timed-out trying to acquire PJSUA mutex (possibly system has deadlocked) in pjsua_call_get_conf_port() and the application hangs. I tried to do all pjsua function calls in an own thread with an self-written sheduler to execute the dialog commands. I tried using PostMessage instead of SendMessage to Singnal back to the Dialog It all had the same effect. If i remove all dialog interaction (using fix wave-files) it all works fine. Any suggestions what I can do? Regards Andreas Werth -- SCP SOFTWARE Systemintegration & Communication Projects www.scp-software.com