Sometimes when I call AudioWorkIntervalCreate the call hangs with the following stacktrace. The call is made on the main thread. mach_msg2_trap 0x00007ff801f0b3ce mach_msg2_internal 0x00007ff801f19d80 mach_msg_overwrite 0x00007ff801f12510 mach_msg 0x00007ff801f0b6bd HALC_Object_AddPropertyListener 0x00007ff8049ea43e HALC_ProxyObject::HALC_ProxyObject(unsigned int, unsigned int, unsigned int, unsigned int) 0x00007ff8047f97f2 HALC_ProxyObjectMap::_CreateObject(unsigned int, unsigned int, unsigned int, unsigned int) 0x00007ff80490f69c HALC_ProxyObjectMap::CopyObjectByObjectID(unsigned int) 0x00007ff80490ecd6 HALC_ShellPlugIn::_ReconcileDeviceList(bool, bool, std::__1::vector<unsigned int, std::__1::allocator<unsigned int>>&, std::__1::vector<unsigned int, std::__1::allocator<unsigned int>>&) 0x00007ff8045d68cf HALB_CommandGate::ExecuteCommand(void () block_pointer) const 0x00007ff80492ed14 HALC_ShellObject::ExecuteCommand(void () block_pointer) const 0x00007ff80470f554 HALC_ShellPlugIn::ReconcileDeviceList(bool, bool) 0x00007ff8045d6414 HALC_ShellPlugIn::ConnectToServer() 0x00007ff8045d74a4 HAL_HardwarePlugIn_InitializeWithObjectID(AudioHardwarePlugInInterface**, unsigned int) 0x00007ff8045da256 HALPlugInManagement::CreateHALPlugIn(HALCFPlugIn const*) 0x00007ff80442f828 HALSystem::InitializeDevices() 0x00007ff80442ebc3 HALSystem::CheckOutInstance() 0x00007ff80442b696 AudioObjectAddPropertyListener_mac_imp 0x00007ff80469b431 auoop::WorkgroupManager_macOS::WorkgroupManager_macOS() 0x00007ff8040fc3d5 auoop::gWorkgroupManager() 0x00007ff8040fc245 AudioWorkIntervalCreate 0x00007ff804034a33