Macbook M1 microphone not working after update

Dante_N wrote:

I have upgraded to Sequoia 15.7.1 (latest), from Monterey on my Macbook M1, and my microphone stopped working. I tried everything, even resetting the microphone using Terminal commands, restarting, but nothing works. It is not a hardware issue, so is gotta be something else. Or maybe it is hardware issue?

For now I use my iPhone as microphone.

It certainly should be working. Based on what you say in your post, I am assuming you have carefully checked all the Settings for Sound already.

Upgrading from Monterey should not be an issue because the MacOS resides in a "sealed" volume that is read only to all users and applications, except certified installers using Apple verified servers. Since that volume is read only, it cannot be changed (except by Apple).

Some standard troubleshooting steps:

• Boot into safe mode. Steps to do this vary according to you Mac model, follow Apple's instructions precisely. Check if sound works in safe mode. Then boot normally and re-check.
• If it works in safe mode but not in normal mode, that indicates that something installed that worked fine under Monterey is conflicting under Sequoia. That is not unusual, as it takes some additional effort to check that all extensions and software are compatible with a new MacOS before upgrading.
• If it doesn't work in safe mode, that might be indicative of a hardware issue. In any case, try to boot into Recovery (again, instructions vary according to Mac model) and then open Disk Utility and run First Aid on your main drive as well as on the other layers of storage, right up to the primary hardware device level (highest level). Take note of any problems found that cannot be repaired and report back.
• You can also, from Recovery, select an option to reinstall the MacOS. Be sure not to select the option to erase and install, select the option to just reinstall. That reinstall should not affect or touch any of your files. Because the MacOS is on a separate sealed volume from your files. But nonetheless, always make a verified backup of all your files before any such reinstall, just in case hardware is failing.
• Try creating a new user. Then log out of your user and log in as the new user. Check for proper operation of the microphone. If it works, there is some setting in your user account that is interfering. If it doesn't work, that again points to hardware, but try the next step before taking it in for service.
• Follow instructions here How to use the Add Text Feature When Post… - Apple Community to run Etrecheck and post its report here using the Additional Text button below. This is an anonymous report about what is installed but it does not reveal any personal or identifying information. This may enable other reader and users here to identify something installed under Monterey that is not compatible with Sequoia and might be causing your issue.

Why would hardware fail around the same time that the MacOS is upgraded? Isn't that too much of a coincidence? Actually, upgrading the MacOS, especially on an older machine (yours must date back some years) is somewhat stressful on the hardware because scores of files (tens of GB) are read in, decompressed, and written, which uses up much if not all the memory and the intensive disk activity, which can go on for tens of minutes, causes the Mac to heat up. If some circuitry or solder joints are marginal, this temperature swing can cause them to separate and stop working properly. For the microphone, it could be one integrated circuit or chip that stopped working. The Hardware is best checked by an Apple Authorized Service Provider but there are some hardware diagnostics that you may be able to run yourself.