"reload" mac audio drivers without rebooting

I have an external audio interface (M-audio fast track c400). In order to get my macbook to recognize it (display in audio/midi setup), I have to reboot, which is a hassle. I have had other m-audio interfaces that were automatically detected when connected, and I'm pretty sure this one should be the same. Most posts around the internet suggest updating the OS or the software/firmware for the device. I have done all of those with no luck. I am currently running OS X 10.8.5.

Is there a way to force OS X to reload the device? Preferably some command line voodoo that I could fire off quickly when needed or wrap up in a nice little shell script.

Edit: Progress..

The problem appears to be fixed now... I'm not sure how the following solved the problem. If you know, please comment!

Inspired by @sbugert's answer, I started looking into other system daemon's that might do the trick if restarted. As a shot in the dark I killed coreservicesd. This caused the OS to become visibly unstable and I was eventually logged out automatically. To my surprise, when I logged back in, my audio interface was recognized..

Based on that, I hypothesized that killing coreservicesd and logging out/in may be a possible (ugly) workaround. So I unplugged the interface and plugged it back in, and as expected, it was not recognized. So I killed coreservicesd and attempted to log out, however I could not get the system to log out due to the instability caused by killing coreservicesd. I eventually was forced to do a "hard" shutdown (i.e. holding the power button until it turns off). After booting up the macbook again, the interface is now recognized automatically every time I plug it in. I suspect that this "hard" reset may have solved the issue without all the shenanigans with the coreservices daemon, but I have no way to test that.

If anyone can shed light on this, please do!

Edit: It stopped working again so I don't know what's up.

6 Answers

EDIT: most likely only works for osx before 10.13

This is what you need,

sudo kextunload /System/Library/Extensions/AppleHDA.kext
sudo kextload /System/Library/Extensions/AppleHDA.kext

But if you want to kill your coreaudio as well,

 ps aux | grep 'coreaudio[d]' | awk '{print $2}' | xargs sudo kill

use with caution.
The grep target is written this way specifically to exclude grepping the grep process itself in the ps out.

17

Try typing this into Terminal:

sudo killall coreaudiod

This will kill the coreaudio process and restart it.

10

The "proper" way to restart coreaudiod is this: sudo launchctl kickstart -kp system/com.apple.audio.coreaudiod

3

Same solution but with different variation

sudo kill -9 `ps ax|grep 'coreaudio[a-z]' | awk '{print $1}'`

1

I have the same interface and that happened to me a lot when I first got it.

I thought the audio drivers in my Mac were the problem, but it was just the way I plugged in the interface.

Every time I wanted to use it, I had to unplug it and plug it back into the computer.

Here I have discovered that if I select another device before disconnecting the interface (Fast Track C400 too), I can connect it again later with no problem. But if I am using the fast track and then disconnect it, it can't connect again until restart it.