Hm, I just got a similar segfault: Thread 45 (process 56199): #0 0x00007fff90228686 in mach_msg_trap () #1 0x00007fff90227c42 in mach_msg () #2 0x00007fff913c170c in HALB_MachPort::SendMessageWithReply () #3 0x00007fff913c169a in HALB_MachPort::SendSimpleMessageWithSimpleReply () #4 0x00007fff913bfad9 in HALC_ProxyIOContext::IOWorkLoop () #5 0x00007fff913bf5bf in HALC_ProxyIOContext::IOThreadEntry () #6 0x00007fff913bf497 in HALB_IOThread::Entry () #7 0x00007fff87f0a772 in _pthread_start () #8 0x00007fff87ef71a1 in thread_start () Thread 41 (process 56199): #0 0x00007fff9022a0fa in __psynch_cvwait () #1 0x00007fff87f0efb9 in _pthread_cond_wait () #2 0x000000010122819c in QWaitConditionPrivate::wait () #3 0x0000000101227ea5 in QWaitCondition::wait () #4 0x0000000101223db3 in QSemaphore::acquire () #5 0x0000000100086cb6 in CachingReaderWorker::run (this=0x131d38390) at src/cachingreaderworker.cpp:124 #6 0x000000010122746a in QThreadPrivate::start () #7 0x00007fff87f0a772 in _pthread_start () #8 0x00007fff87ef71a1 in thread_start () Thread 40 (process 56199): #0 0x00007fff9022a0fa in __psynch_cvwait () #1 0x00007fff87f0efb9 in _pthread_cond_wait () #2 0x000000010122819c in QWaitConditionPrivate::wait () #3 0x0000000101227ea5 in QWaitCondition::wait () #4 0x0000000101223db3 in QSemaphore::acquire () #5 0x0000000100086cb6 in CachingReaderWorker::run (this=0x13024b050) at src/cachingreaderworker.cpp:124 #6 0x000000010122746a in QThreadPrivate::start () #7 0x00007fff87f0a772 in _pthread_start () #8 0x00007fff87ef71a1 in thread_start () Thread 39 (process 56199): #0 0x00007fff9022a0fa in __psynch_cvwait () #1 0x00007fff87f0efb9 in _pthread_cond_wait () #2 0x000000010122819c in QWaitConditionPrivate::wait () #3 0x0000000101227ea5 in QWaitCondition::wait () #4 0x0000000101223db3 in QSemaphore::acquire () #5 0x0000000100086cb6 in CachingReaderWorker::run (this=0x12a23a460) at src/cachingreaderworker.cpp:124 #6 0x000000010122746a in QThreadPrivate::start () #7 0x00007fff87f0a772 in _pthread_start () #8 0x00007fff87ef71a1 in thread_start () Thread 38 (process 56199): #0 0x00007fff9022a0fa in __psynch_cvwait () #1 0x00007fff87f0efb9 in _pthread_cond_wait () #2 0x000000010122819c in QWaitConditionPrivate::wait () #3 0x0000000101227ea5 in QWaitCondition::wait () #4 0x0000000101223db3 in QSemaphore::acquire () #5 0x0000000100086cb6 in CachingReaderWorker::run (this=0x12f22fdf0) at src/cachingreaderworker.cpp:124 #6 0x000000010122746a in QThreadPrivate::start () #7 0x00007fff87f0a772 in _pthread_start () #8 0x00007fff87ef71a1 in thread_start () Thread 37 (process 56199): #0 0x00007fff9022a0fa in __psynch_cvwait () #1 0x00007fff87f0efb9 in _pthread_cond_wait () #2 0x000000010122819c in QWaitConditionPrivate::wait () #3 0x0000000101227ea5 in QWaitCondition::wait () #4 0x0000000101223db3 in QSemaphore::acquire () #5 0x0000000100086cb6 in CachingReaderWorker::run (this=0x12dd43bb0) at src/cachingreaderworker.cpp:124 #6 0x000000010122746a in QThreadPrivate::start () #7 0x00007fff87f0a772 in _pthread_start () #8 0x00007fff87ef71a1 in thread_start () Thread 36 (process 56199): #0 0x00007fff9022a0fa in __psynch_cvwait () #1 0x00007fff87f0efb9 in _pthread_cond_wait () #2 0x000000010122819c in QWaitConditionPrivate::wait () #3 0x0000000101227ea5 in QWaitCondition::wait () #4 0x0000000101223db3 in QSemaphore::acquire () #5 0x0000000100086cb6 in CachingReaderWorker::run (this=0x12c458890) at src/cachingreaderworker.cpp:124 #6 0x000000010122746a in QThreadPrivate::start () #7 0x00007fff87f0a772 in _pthread_start () #8 0x00007fff87ef71a1 in thread_start () Thread 35 (process 56199): #0 0x00007fff9022a0fa in __psynch_cvwait () #1 0x00007fff87f0efb9 in _pthread_cond_wait () #2 0x000000010122819c in QWaitConditionPrivate::wait () #3 0x0000000101227ea5 in QWaitCondition::wait () #4 0x0000000101223db3 in QSemaphore::acquire () #5 0x0000000100086cb6 in CachingReaderWorker::run (this=0x12986d010) at src/cachingreaderworker.cpp:124 #6 0x000000010122746a in QThreadPrivate::start () #7 0x00007fff87f0a772 in _pthread_start () #8 0x00007fff87ef71a1 in thread_start () Thread 34 (process 56199): #0 0x00007fff9022a0fa in __psynch_cvwait () #1 0x00007fff87f0efb9 in _pthread_cond_wait () #2 0x000000010122819c in QWaitConditionPrivate::wait () #3 0x0000000101227ea5 in QWaitCondition::wait () #4 0x0000000101223db3 in QSemaphore::acquire () #5 0x0000000100086cb6 in CachingReaderWorker::run (this=0x111b78ca0) at src/cachingreaderworker.cpp:124 #6 0x000000010122746a in QThreadPrivate::start () #7 0x00007fff87f0a772 in _pthread_start () #8 0x00007fff87ef71a1 in thread_start () Thread 33 (process 56199): #0 0x00007fff9022a0fa in __psynch_cvwait () #1 0x00007fff87f0efb9 in _pthread_cond_wait () #2 0x000000010122819c in QWaitConditionPrivate::wait () #3 0x0000000101227ea5 in QWaitCondition::wait () #4 0x0000000101223db3 in QSemaphore::acquire () #5 0x0000000100086cb6 in CachingReaderWorker::run (this=0x1247c4db0) at src/cachingreaderworker.cpp:124 #6 0x000000010122746a in QThreadPrivate::start () #7 0x00007fff87f0a772 in _pthread_start () #8 0x00007fff87ef71a1 in thread_start () Thread 32 (process 56199): #0 0x00007fff9022a0fa in __psynch_cvwait () #1 0x00007fff87f0efb9 in _pthread_cond_wait () #2 0x000000010122819c in QWaitConditionPrivate::wait () #3 0x0000000101227ea5 in QWaitCondition::wait () #4 0x0000000101223db3 in QSemaphore::acquire () #5 0x0000000100086cb6 in CachingReaderWorker::run (this=0x11fe30e20) at src/cachingreaderworker.cpp:124 #6 0x000000010122746a in QThreadPrivate::start () #7 0x00007fff87f0a772 in _pthread_start () #8 0x00007fff87ef71a1 in thread_start () Thread 31 (process 56199): #0 0x00007fff9022a0fa in __psynch_cvwait () #1 0x00007fff87f0efb9 in _pthread_cond_wait () #2 0x000000010122819c in QWaitConditionPrivate::wait () #3 0x0000000101227ea5 in QWaitCondition::wait () #4 0x0000000101223db3 in QSemaphore::acquire () #5 0x0000000100086cb6 in CachingReaderWorker::run (this=0x11f27f890) at src/cachingreaderworker.cpp:124 #6 0x000000010122746a in QThreadPrivate::start () #7 0x00007fff87f0a772 in _pthread_start () #8 0x00007fff87ef71a1 in thread_start () Thread 30 (process 56199): #0 0x00007fff9022a0fa in __psynch_cvwait () #1 0x00007fff87f0efb9 in _pthread_cond_wait () #2 0x000000010122819c in QWaitConditionPrivate::wait () #3 0x0000000101227ea5 in QWaitCondition::wait () #4 0x0000000101223db3 in QSemaphore::acquire () #5 0x0000000100086cb6 in CachingReaderWorker::run (this=0x11fa54db0) at src/cachingreaderworker.cpp:124 #6 0x000000010122746a in QThreadPrivate::start () #7 0x00007fff87f0a772 in _pthread_start () #8 0x00007fff87ef71a1 in thread_start () Thread 25 (process 56199): #0 0x00007fff90228686 in mach_msg_trap () #1 0x00007fff90227c42 in mach_msg () #2 0x000000010336a970 in XServerMachPort::ReceiveMessage () #3 0x0000000103386b23 in MIDIProcess::RunMIDIInThread () #4 0x000000010336bc2c in XThread::RunHelper () #5 0x000000010336b80f in CAPThread::Entry () #6 0x00007fff87f0a772 in _pthread_start () #7 0x00007fff87ef71a1 in thread_start () Thread 24 (process 56199): #0 0x00007fff9022a0fa in __psynch_cvwait () #1 0x00007fff87f0efb9 in _pthread_cond_wait () #2 0x0000000102497ff7 in QTWTF::TCMalloc_PageHeap::scavengerThread () #3 0x000000010249809b in QTWTF::TCMalloc_PageHeap::runScavengerThread () #4 0x00007fff87f0a772 in _pthread_start () #5 0x00007fff87ef71a1 in thread_start () Thread 23 (process 56199): #0 0x00007fff9022a0fa in __psynch_cvwait () #1 0x00007fff87f0efb9 in _pthread_cond_wait () #2 0x000000010122819c in QWaitConditionPrivate::wait () #3 0x0000000101227ea5 in QWaitCondition::wait () #4 0x0000000101223db3 in QSemaphore::acquire () #5 0x0000000100086cb6 in CachingReaderWorker::run (this=0x11b839ce0) at src/cachingreaderworker.cpp:124 #6 0x000000010122746a in QThreadPrivate::start () #7 0x00007fff87f0a772 in _pthread_start () #8 0x00007fff87ef71a1 in thread_start () Thread 22 (process 56199): #0 0x00007fff9022a0fa in __psynch_cvwait () #1 0x00007fff87f0efb9 in _pthread_cond_wait () #2 0x000000010122819c in QWaitConditionPrivate::wait () #3 0x0000000101227ea5 in QWaitCondition::wait () #4 0x0000000101223db3 in QSemaphore::acquire () #5 0x0000000100086cb6 in CachingReaderWorker::run (this=0x10e042630) at src/cachingreaderworker.cpp:124 #6 0x000000010122746a in QThreadPrivate::start () #7 0x00007fff87f0a772 in _pthread_start () #8 0x00007fff87ef71a1 in thread_start () Thread 20 (process 56199): #0 0x00007fff9022a0fa in __psynch_cvwait () #1 0x00007fff87f0efb9 in _pthread_cond_wait () #2 0x000000010122819c in QWaitConditionPrivate::wait () #3 0x0000000101227ea5 in QWaitCondition::wait () #4 0x0000000101223db3 in QSemaphore::acquire () #5 0x000000010064c15b in VSyncThread::run (this=0x11920a480) at src/waveform/vsyncthread.cpp:68 #6 0x000000010122746a in QThreadPrivate::start () #7 0x00007fff87f0a772 in _pthread_start () #8 0x00007fff87ef71a1 in thread_start () Thread 18 (process 56199): #0 0x00007fff9022a322 in select$DARWIN_EXTSN () #1 0x0000000101346236 in qt_safe_select () #2 0x000000010134a844 in QEventDispatcherUNIXPrivate::doSelect () #3 0x000000010134ac20 in QEventDispatcherUNIX::processEvents () #4 0x0000000101319c58 in QEventLoop::exec () #5 0x00000001012246c6 in QThread::exec () #6 0x000000010122746a in QThreadPrivate::start () #7 0x00007fff87f0a772 in _pthread_start () #8 0x00007fff87ef71a1 in thread_start () Thread 17 (process 56199): #0 0x00007fff87f29fe6 in szone_free_definite_size () #1 0x00007fff87f238c8 in free () #2 0x00007fff897180f0 in MP3ID3CallbackProc () #3 0x00007fff8978f4ed in ID3ParserHandle::CallReadProcForMoreFrames () #4 0x00007fff8978f1a9 in ID3ParserHandle::ID3API_GetProperty () #5 0x00007fff8971710f in MPEGAudioFile::ParseFirstPacket () #6 0x00007fff8971771e in MPEGAudioFile::ParseAudioFile () #7 0x00007fff897201af in AudioFileObject::DoOpen () #8 0x00007fff8971e69c in AudioFileOpenURL () #9 0x00007fff8972d7e2 in ExtAudioFile::Open () #10 0x00007fff897265ad in ExtAudioFileOpenURL () #11 0x00000001005e7d0a in SoundSourceCoreAudio::open (this=0x1363f4290) at src/soundsourcecoreaudio.cpp:45 #12 0x00000001005ed6f5 in SoundSourceProxy::open (this=0x134cc6940) at src/soundsourceproxy.cpp:267 #13 0x0000000100067d40 in AnalyserQueue::run (this=0x10353e870) at src/analyserqueue.cpp:295 #14 0x000000010122746a in QThreadPrivate::start () #15 0x00007fff87f0a772 in _pthread_start () #16 0x00007fff87ef71a1 in thread_start () Thread 16 (process 56199): #0 0x00007fff9022a0fa in __psynch_cvwait () #1 0x00007fff87f0efb9 in _pthread_cond_wait () #2 0x000000010122819c in QWaitConditionPrivate::wait () #3 0x0000000101227ea5 in QWaitCondition::wait () #4 0x0000000100437ac7 in BrowseThread::run (this=0x1188ea450) at src/library/browse/browsethread.cpp:82 #5 0x000000010122746a in QThreadPrivate::start () #6 0x00007fff87f0a772 in _pthread_start () #7 0x00007fff87ef71a1 in thread_start () Thread 15 (process 56199): #0 0x00007fff9022a0fa in __psynch_cvwait () #1 0x00007fff87f0efb9 in _pthread_cond_wait () #2 0x000000010122819c in QWaitConditionPrivate::wait () #3 0x0000000101227ea5 in QWaitCondition::wait () #4 0x0000000101223db3 in QSemaphore::acquire () #5 0x0000000100086cb6 in CachingReaderWorker::run (this=0x1178e51c0) at src/cachingreaderworker.cpp:124 #6 0x000000010122746a in QThreadPrivate::start () #7 0x00007fff87f0a772 in _pthread_start () #8 0x00007fff87ef71a1 in thread_start () Thread 14 (process 56199): #0 0x00007fff9022a0fa in __psynch_cvwait () #1 0x00007fff87f0efb9 in _pthread_cond_wait () #2 0x000000010122819c in QWaitConditionPrivate::wait () #3 0x0000000101227ea5 in QWaitCondition::wait () #4 0x0000000101223db3 in QSemaphore::acquire () #5 0x0000000100086cb6 in CachingReaderWorker::run (this=0x1156f7e30) at src/cachingreaderworker.cpp:124 #6 0x000000010122746a in QThreadPrivate::start () #7 0x00007fff87f0a772 in _pthread_start () #8 0x00007fff87ef71a1 in thread_start () Thread 13 (process 56199): #0 0x00007fff9022a0fa in __psynch_cvwait () #1 0x00007fff87f0efb9 in _pthread_cond_wait () #2 0x000000010122819c in QWaitConditionPrivate::wait () #3 0x0000000101227ea5 in QWaitCondition::wait () #4 0x0000000101223db3 in QSemaphore::acquire () #5 0x0000000100086cb6 in CachingReaderWorker::run (this=0x11560eb10) at src/cachingreaderworker.cpp:124 #6 0x000000010122746a in QThreadPrivate::start () #7 0x00007fff87f0a772 in _pthread_start () #8 0x00007fff87ef71a1 in thread_start () Thread 12 (process 56199): #0 0x00007fff9022a0fa in __psynch_cvwait () #1 0x00007fff87f0efb9 in _pthread_cond_wait () #2 0x000000010122819c in QWaitConditionPrivate::wait () #3 0x0000000101227ea5 in QWaitCondition::wait () #4 0x0000000101223db3 in QSemaphore::acquire () #5 0x0000000100086cb6 in CachingReaderWorker::run (this=0x114321880) at src/cachingreaderworker.cpp:124 #6 0x000000010122746a in QThreadPrivate::start () #7 0x00007fff87f0a772 in _pthread_start () #8 0x00007fff87ef71a1 in thread_start () Thread 11 (process 56199): #0 0x00007fff9022a0fa in __psynch_cvwait () #1 0x00007fff87f0efb9 in _pthread_cond_wait () #2 0x000000010122819c in QWaitConditionPrivate::wait () #3 0x0000000101227ea5 in QWaitCondition::wait () #4 0x0000000101223db3 in QSemaphore::acquire () #5 0x0000000100086cb6 in CachingReaderWorker::run (this=0x112d34370) at src/cachingreaderworker.cpp:124 #6 0x000000010122746a in QThreadPrivate::start () #7 0x00007fff87f0a772 in _pthread_start () #8 0x00007fff87ef71a1 in thread_start () Thread 10 (process 56199): #0 0x00000001000869df in CachingReaderWorker::processChunkReadRequest (this=0x111c470c0, request=0x112c50e90, update=0x112c50e68) at src/cachingreaderworker.cpp:93 #1 0x0000000100086c7c in CachingReaderWorker::run (this=0x111c470c0) at src/cachingreaderworker.cpp:121 #2 0x000000010122746a in QThreadPrivate::start () #3 0x00007fff87f0a772 in _pthread_start () #4 0x00007fff87ef71a1 in thread_start () Thread 9 (process 56199): #0 0x00007fff9022a0fa in __psynch_cvwait () #1 0x00007fff87f0efb9 in _pthread_cond_wait () #2 0x000000010122819c in QWaitConditionPrivate::wait () #3 0x0000000101227ea5 in QWaitCondition::wait () #4 0x0000000101223db3 in QSemaphore::acquire () #5 0x0000000100086cb6 in CachingReaderWorker::run (this=0x1093f7920) at src/cachingreaderworker.cpp:124 #6 0x000000010122746a in QThreadPrivate::start () #7 0x00007fff87f0a772 in _pthread_start () #8 0x00007fff87ef71a1 in thread_start () Thread 8 (process 56199): #0 0x00007fff9022a0fa in __psynch_cvwait () #1 0x00007fff87f0efb9 in _pthread_cond_wait () #2 0x000000010122819c in QWaitConditionPrivate::wait () #3 0x0000000101227ea5 in QWaitCondition::wait () #4 0x0000000100624e51 in VinylControlProcessor::run (this=0x1093d0bb0) at src/vinylcontrol/vinylcontrolprocessor.cpp:130 #5 0x000000010122746a in QThreadPrivate::start () #6 0x00007fff87f0a772 in _pthread_start () #7 0x00007fff87ef71a1 in thread_start () Thread 7 (process 56199): #0 0x00007fff9022a0fa in __psynch_cvwait () #1 0x00007fff87f0efb9 in _pthread_cond_wait () #2 0x000000010122819c in QWaitConditionPrivate::wait () #3 0x0000000101227ea5 in QWaitCondition::wait () #4 0x00000001003cf52e in EngineSideChain::run (this=0x1041f2c10) at src/engine/sidechain/enginesidechain.cpp:93 #5 0x000000010122746a in QThreadPrivate::start () #6 0x00007fff87f0a772 in _pthread_start () #7 0x00007fff87ef71a1 in thread_start () Thread 6 (process 56199): #0 0x00007fff9022a0fa in __psynch_cvwait () #1 0x00007fff87f0efb9 in _pthread_cond_wait () #2 0x000000010122819c in QWaitConditionPrivate::wait () #3 0x0000000101227ea5 in QWaitCondition::wait () #4 0x00000001003ae417 in EngineWorkerScheduler::run (this=0x10418a460) at src/engine/engineworkerscheduler.cpp:43 #5 0x000000010122746a in QThreadPrivate::start () #6 0x00007fff87f0a772 in _pthread_start () #7 0x00007fff87ef71a1 in thread_start () Thread 5 (process 56199): #0 0x00007fff9022a0fa in __psynch_cvwait () #1 0x00007fff87f0efb9 in _pthread_cond_wait () #2 0x000000010122819c in QWaitConditionPrivate::wait () #3 0x0000000101227ea5 in QWaitCondition::wait () #4 0x00000001006188ee in StatsManager::run (this=0x1041d2500) at src/util/statsmanager.cpp:97 #5 0x000000010122746a in QThreadPrivate::start () #6 0x00007fff87f0a772 in _pthread_start () #7 0x00007fff87ef71a1 in thread_start () Thread 2 (process 56199): #0 0x00007fff9022ad16 in kevent () #1 0x00007fff93c37dea in _dispatch_mgr_invoke () #2 0x00007fff93c379ee in _dispatch_mgr_thread () Thread 1 (process 56199): #0 0x000000018d69c46a in ?? () Cannot access memory at address 0x18d69c46a #1 0x00007fff8d69c135 in DoDropMessage () #2 0x00007fff8d69c0d7 in SendDropMessage () #3 0x00007fff8d69f7c8 in DragInApplication () #4 0x00007fff8d69ec69 in CoreDragStartDragging () #5 0x00007fff8debc120 in -[NSCoreDragManager _dragUntilMouseUp:accepted:] () #6 0x00007fff8debd44a in -[NSCoreDragManager dragImage:fromWindow:at:offset:event:pasteboard:source:slideBack:] () #7 0x00007fff8e16cfd0 in -[NSWindow(NSDrag) dragImage:at:offset:event:pasteboard:source:slideBack:] () #8 0x000000010156d6c9 in QDragManager::drag () #9 0x00000001015d55a9 in QDrag::exec () #10 0x00000001015d55d8 in QDrag::exec () #11 0x000000010069bb0a in WTrackTableView::mouseMoveEvent (this=0x1251c8000, pEvent=0x7fff5fbfe880) at src/widget/wtracktableview.cpp:834 #12 0x0000000101610038 in QWidget::event () #13 0x0000000101965ac2 in QFrame::event () #14 0x00000001019e4c04 in QAbstractScrollArea::viewportEvent () #15 0x0000000101a6d957 in QAbstractItemView::viewportEvent () #16 0x00000001019e6fed in QAbstractScrollAreaFilter::eventFilter () #17 0x000000010131a321 in QCoreApplicationPrivate::sendThroughObjectEventFilters () #18 0x00000001015c16c8 in QApplicationPrivate::notify_helper () #19 0x00000001015c2128 in QApplication::notify () #20 0x000000010131c8d2 in QCoreApplication::notifyInternal () #21 0x00000001015c9e3e in QApplicationPrivate::sendMouseEvent () #22 0x0000000101578671 in qt_mac_handleMouseEvent () #23 0x00007fff8dc4fb81 in -[NSWindow sendEvent:] () #24 0x000000010156fde2 in -[QCocoaWindow sendEvent:] () #25 0x00007fff8dc4b644 in -[NSApplication sendEvent:] () #26 0x0000000101573702 in -[QNSApplication sendEvent:] () #27 0x00007fff8db6121a in -[NSApplication run] () #28 0x000000010157c970 in QEventDispatcherMac::processEvents () #29 0x0000000101319c58 in QEventLoop::exec () #30 0x000000010131d023 in QCoreApplication::exec () #31 0x000000010053a7a3 in main (argc=2, argv=0x7fff5fbff2c8) at src/main.cpp:294 Stack frame #0 of Thread 1 is at memory address 0x000000018d69c46a which if you look at the frame preceding it looks like it ought to have a high-DWORD of 0x00007fff but it has been overwritten as a 0x1.