In another thread I mentioned: Rui needs help reproducing this bug: "Crash after changing audio bus - ID: 3021645)" http://sourceforge.net/tracker/?func=detail&atid=733076&aid=30216... If interested, please enable gdb coredumps and send backtraces in reply-all to this thread. To do this you need (1) Build from subversion a debug build: http://qtractor.sourceforge.net/qtractor-downloads.html#SVN and compile using http://qtractor.sourceforge.net/qtractor-index.html#Installation but with "/configure --enable-debug" (2) do command ' bash -c "ulimit -c" ' If it returns 0, do ' bash -c "ulimit -c unlimited" ' (3) Run Qtractor and attempt to reproduce the problem: In my case, the crash, however, isn't happeing in qtractor, it's happeing in jack2 -- which in this case for simplicitly, I'm letting qtractor startup w/o qjackctl. ( jack-audio-connection-kit-1.9.4-1.fc12.ccrma.x86_64 ) Below is the qtractor log output that happens after I go to "VIew -> Buses..." , select "Audio Master" -> "Audio" -> "Channels" --> "12" -> "Update" If I were to save the template containing these settings, I could startup qtractor in 12 channel mode. It's the updating of master bus from 2-> 12 that causes jackd to die, takes everything else down with it, and forces you to save and restart qtractor. ............. 13:05:35.220 Open session: "Untitled1". 13:05:36.689 Session started. Cannot connect to server socket err = Connection refused Cannot connect to server socket Cannot connect to server socket err = Connection refused Cannot connect to server socket no message buffer overruns no message buffer overruns jackdmp 1.9.4 Copyright 2001-2005 Paul Davis and others. Copyright 2004-2009 Grame. jackdmp comes with ABSOLUTELY NO WARRANTY This is free software, and you are welcome to redistribute it under certain conditions; see the file COPYING for details JACK server starting in realtime mode with priority 60 audio_reservation_init Acquire audio card Audio2 creating alsa driver ... hw:M66|hw:M66|256|2|44100|0|0|hwmon|hwmeter|-|32bit Using ALSA driver ICE1712 running on card 2 - M Audio Delta 66 at 0xec00, irq 21 configuring for 44100Hz, period = 256 frames (5.8 ms), buffer = 2 periods ALSA: final selected sample format for capture: 32bit integer little-endian ALSA: use 2 periods for capture ALSA: final selected sample format for playback: 32bit integer little-endian ALSA: use 2 periods for playback port created: Midi-Through:midi/playback_1 port created: Midi-Through:midi/capture_1 port created: MT4:midi/playback_1 port created: MT4:midi/capture_1 port created: MT4:midi/playback_2 port created: MT4:midi/capture_2 port created: MT4:midi/playback_3 port created: MT4:midi/capture_3 port created: MT4:midi/capture_4 port created: MT4:midi/capture_5 port created: BCD3000:midi/playback_1 port created: BCD3000:midi/capture_1 port created: UM-2:midi/playback_1 port created: UM-2:midi/capture_1 port created: UM-2:midi/playback_2 port created: UM-2:midi/capture_2 port created: QmidiNet:midi/playback_1 port created: QmidiNet:midi/capture_1 port created: QmidiNet:midi/playback_2 port created: QmidiNet:midi/capture_2 port created: QMidiRoute:midi/capture_1 port created: QMidiRoute:midi/playback_2 port created: QMidiRoute:midi/playback_3 port created: Qtractor:midi/playback_1 port created: Qtractor:midi/playback_2 port created: Qtractor:midi/capture_2 port created: Qtractor:midi/playback_3 port created: Qtractor:midi/playback_4 port created: Qtractor:midi/capture_4 port created: Qtractor:midi/playback_5 port created: Qtractor:midi/capture_5 13:05:37.169 Audio connections change. 13:05:37.176 MIDI connections change. 13:05:51.799 The audio engine has been shutdown. Make sure the JACK audio server (jackd) is up and running and then restart session. JackClientSocket::Read time out JackClientSocket::Read time out Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Could not read result type = 1 Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Could not read result type = 1 Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Could not read result type = 1 Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Could not read result type = 1 JackSocketClientChannel read fail Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Could not read result type = 7 Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Could not read result type = 2 Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Could not read result type = 2 Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Could not read result type = 2 Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Could not read result type = 2 Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Could not read result type = 2 Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Could not read result type = 2 Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Could not read result type = 2 Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Could not read result type = 2 Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Could not read result type = 2 Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Could not read result type = 2 Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Could not read result type = 2 Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Could not read result type = 2 Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Could not read result type = 2 Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Could not read result type = 2 Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Could not read result type = 2 Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Could not read result type = 2 Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Could not read result type = 2 Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Could not read result type = 2 Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Could not read result type = 2 Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Could not read result type = 2 Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Cannot write socket fd = 12 err = Broken pipe Could not read result type = 2 13:05:51.971 Audio connections change. ..................... Above happening off current subversion trunk: "At revision 1597." Niels http://nielsmayer.com