Hi, Example code of AudioDriverKit from WWDC2021 stopped to work correctly for me. It builds and loads but when I want to record sine wave immediately after startIO function stopIO is called. It happens on both MacBook Air and Mac mini with macOS 12.0.1. I discovered it because my audio driver also stopped to work correctly - exactly the same problem I described above. Earlier I was testing both example code and my audio driver on macOS 12 public beta and everything was ok. Below I paste logs from console when I start recording: default 12:54:19.161261+0100 kernel StartIO: Start IO: device 2 default 12:54:19.161274+0100 kernel StartIO: Start IO: device 2 default 12:54:19.161092+0100 coreaudiod HALS_IOEngine2::StartIO: starting IO on device SimpleAudioDevice-UID default 12:54:19.161279+0100 kernel StartIO: Start IO: device 2 default 12:54:19.161138+0100 coreaudiod HALS_IOEngine2::_StartIO(435) on Context 443 state: Prewarm: 0 Play: 0 State: Stopped default 12:54:19.161374+0100 CAReportingService CAReportingService.mm:157 service type 9 set for reporter 897648164879 default 12:54:19.161437+0100 coreaudiod HALS_IOEngine2::_StartIO(435) on Context 443 state: Prewarm: 0 Play: 1 State: Running default 12:54:19.161761+0100 coreaudiod HALS_Device::_GetCombinedVolumeScalar: client 246 (pid 517) is not present and has a combined volume scalar is 1.000000 default 12:54:19.161798+0100 coreaudiod HALS_Device::_GetCombinedVolumeScalar: client 246 (pid 517) is not present and has a combined volume scalar is 1.000000 default 12:54:19.161808+0100 coreaudiod HALS_IOUADevice::HandlePropertiesChanged: Object: 431: SimpleAudioDevice-UID default 12:54:19.162034+0100 coreaudiod 'goin', 'glob', 0 default 12:54:19.162580+0100 coreaudiod CAReportingClient.mm:508 message { "device_is_aggregate" = 0; "input_avail_phys_formats" = "{ [16/48000/1 lpcm], [16/44100/1 lpcm] }"; "input_avail_virt_formats" = "{ [32/48000/1 lpcm], [32/44100/1 lpcm] }"; "input_bits_per_channel" = 32; "input_bytes_per_frame" = 4; "input_bytes_per_packet" = 4; "input_channels_per_frame" = 1; "input_device_source_list" = Unknown; "input_device_transport_list" = BuiltIn; "input_device_uid_list" = "SimpleAudioDevice-UID"; "input_format_id" = lpcm; "input_frames_per_packet" = 1; "input_num_tap_streams" = 0; "input_scalar_volume" = "1.000000"; "io_buffer_size" = 15; message = StartHardware; "output_num_tap_streams" = 0; "output_scalar_volume" = "1.000000"; "sample_rate" = 48000; }: ( 897648164879 ) error 12:54:19.163011+0100 coreaudiod 206515 HALS_IOUAUCDriver.cpp:500 Throwing Exception: ret != kIOReturnSuccess Failed to register event link error 12:54:19.163100+0100 coreaudiod 206515 HALS_IOUAEngine.cpp:157 Failed to register io thread! default 12:54:19.163950+0100 kernel StopIO: Stop IO: device 2 default 12:54:19.163968+0100 kernel StopIO: Stop IO: device 2 default 12:54:19.163974+0100 kernel StopIO: Stop IO: device 2 default 12:54:19.163166+0100 coreaudiod HALS_IOContext_Legacy_Impl::IOWorkLoop: failed to register io thread error 12:54:19.163310+0100 coreaudiod 206515 HALS_IOUAEngine.cpp:180 Throwing Exception: error != 0 Failed to disassociate event link 22 error 12:54:19.163482+0100 coreaudiod 206515 HALS_IOUAEngine.cpp:187 Failed to unregister io thread! default 12:54:19.163613+0100 coreaudiod HALS_IOEngine2::StopIO: stopping IO on device SimpleAudioDevice-UID default 12:54:19.163744+0100 coreaudiod HALS_IOEngine2::_StopIO(435) on Context 443 state: Prewarm: 0 Play: 1 State: Running default 12:54:19.164082+0100 coreaudiod HALS_IOUADevice::HandlePropertiesChanged: Object: 431: SimpleAudioDevice-UID default 12:54:19.164134+0100 coreaudiod 'goin', 'glob', 0 default 12:54:19.164289+0100 coreaudiod CAReportingClient.mm:480 stopping ( 897648164879 ) default 12:54:19.164542+0100 coreaudiod CAReportingClient.mm:508 message { "session_duration" = "0.003519058227539062"; }: ( 897648164879 ) error 12:54:19.165611+0100 Audacity HALC_ProxyIOContext::IOWorkLoop: the server failed to start, Error: 0x77686174 default 12:54:19.165045+0100 coreaudiod IO Stopped Context 443 after 0 frames. default 12:54:19.165199+0100 coreaudiod HALS_IOContext_Legacy_Impl::IOThreadEntry: 443 SimpleAudioDevice-UID (SimpleAudioDevice-UID): stopping with error 2003329396 default 12:54:19.165220+0100 coreaudiod HALB_PowerAssertion::Release: releasing power assertion ID 34859 of type 'PreventUserIdleSystemSleep' with name: 'com.apple.audio.context443.preventuseridlesleep' on behalf of 517 error 12:54:19.165390+0100 coreaudiod HALS_IOContext_Legacy_Impl::StartIOThread: the IO thread failed to start, Error: 2003329396 (what) Any advice? Thank you and regards

Hello, I rewriting a audio driver that was created in IOKit to a new one based on AudioDriverKit. I would like to block possibility to connect multiple devices to the computer so that driver support just one device. In IOKit it was done by overriding IOAudioEngine::getLocalUniqueID() method and I cannot find anything similar in AudioDriverKit (IOUserAudioDevice). Do you know how to do it? Best Regards