Audio settings in High Sierra resetting after reboot

I have this issue where my selected audio device will reset to Digital Out after I restart.

I have searched online and found some people suggesting deleting some configuration file for older versions of Mac OS, but the file doesn't exist in my computer.

Anyone knows what file holds these settings so I can see if it's a permissions problem?

Or if anyone knows what the true solution is please let me know.

thanks.

Solution 1:

If the audio device you're using is always connected, please try these instructions (relevant portion below, although there are some other suggestions in that post that could be worth trying).

However, keep in mind that if the device is disconnected when your system starts, it will revert to the system default. (It is also possible, that if you are loading certain applications on startup, that they are resetting the preferred default, but we'll need more details on your system configuration/startup items in this case.)

You could also, depending on your situation, use an AppleScript method to create a one-click type approach to your audio selection.

Suggested first attempt to solve this issue:

Go to /Applications/Utilities and open Audio MIDI Setup. Select the device you want to use, click the gear, and then Use this device for sound output.

Solution 2:

You can try reset your SMC and NVRAM. It will bring your system to default settings overriding any plist entry which is causing unwanted device to take priority.

Reset SMC

Shut Down your Mac.
Press Shift + Control + Option + Power button at the same time. 
Release all keys and the power button at the same time.

6) Reset NVRAM

Shut down your Mac.
Press the power button.
Before the grey screen appears, press the Command, Option, P, and R keys at the same time.
Hold the keys until your computer restarts and you hear the startup sound a second time. 
Release the keys.