12-05-2017 04:19 AM
I have the same problem with my Hero 5 Black, random video clips missing audio and I use quick capture because it is so much handier when I am mountain biking. If what you said is correct, GoPro needs to fix that issue.
04-12-2018 11:38 AM
Are you using an external mic by any chance? See: https://gopro.com/help/articles/block/HERO5-Black-External-Microphone-Information
Here are some troubleshooting steps to get your camera paired. In most cases, forgetting the Wi-Fi name and the Bluetooth ID resolves the issue.
Should you need further assistance, contact our Support Team. You may reach them via phone or chat. https://gopro.com/help/ContactUs
05-06-2018 07:17 AM
Very similar problem here, except MOST of my videos have no sound. It will actually lose sound at some moment in the day, during a video, and after that all recordings have no sound at all. It loses the sound in the middle of recording, without any action of any kind from my part.
I do not use the app, I do not use external mic. I use a SanDisk Ultra class 10 64GB.
05-06-2018 07:47 AM
See if using a recommended SD card helps resolve the intermittent audio issue. Try doing a manual update on your camera and make sure that you are using an SD card that works with the HERO5 Black camera. You can follow this link for guide on the manual update: https://gopro.com/help/articles/how_to/Software-Update-Instructions-for-HERO5-Cameras
Let us know how it goes.
07-26-2018 12:43 AM
Same issue here, I will record 6 or 7 videos and 1 or 2 will have no sound at all, firmware is uptodate, I am using a recommended SD card, I am powering up the gopro then recording (not using quick capture). I have tried using the audio set to auto and also wind but it makes no difference. Used on a chest mount mountainbiking with image stabilisation on protune ON (not that it should make any difference)