Starting a Quicktime Audio recording with Catalina Dev Beta 5 on 2018 or later Macbook Pros outputs files with no sound (Macbook Pro Microhone selected). Example file here: https://www.dropbox.com/s/ib67k0vg8cm93fn/test_no_audio%20%281%29.aifc?dl=0

During the recording recording Console shows this error:

"CMIO_Unit_Converter_Audio.cpp:590:RebuildAudioConverter AudioConverterSetProperty() failed (1886547824)"

We have an application that records the screen and audio at the same time using AVFoundation and the resulting video files also do not have audio. However when inspecting the CMSampleBuffers, they seem fine: https://gist.github.com/paulius005/faef6d6250323b7d3386a9a70c08f70b

Is anyone else experiencing this issue or possibly have more visibility if it's something Apple is working on?

Anything else that I should be looking at to tackle the issue?

  • I just tried a test recording on Catabline dev beta 5 using Quicktime. I don't have any problem with either recording or playback. I used my 2015 MBP mic. Maybe it's something specific to your device or how you're doing it?
    – fsb
    Commented Aug 3, 2019 at 13:36
  • Hey @fsb I've tested this on 3 different 2018 MBPs with their internal mic and non of them work. It works fine if using an external mic though :( Commented Aug 3, 2019 at 15:22
  • That's really strange. I'm just opening QuickTime, making a short audio recording using the built-in mic, saving the file, then playing it. Works fine. I have a 2015 MBP so maybe it's that?
    – fsb
    Commented Aug 3, 2019 at 19:21
  • Yep yep, on older devices it works just fine Commented Aug 3, 2019 at 20:53
  • I have MacOS Catalina Beta 5 (19A526h) and QuickTime refuses to record audio. It's not a permission problem because QuickTIme very explicitly tells you if it does not have access to your mike. I only have an internal mike. No external audio devices whatsoever. I am also using a 2018 Macbook Pro. Commented Aug 8, 2019 at 18:01

1 Answer 1


There are new beta updates. Can you check them and see if the issue persists.


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