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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!
The kext changes caused my laptop to reset - I don't recommend it. The fix for me was to go to
Settings > Sound
and check the Output is set correctly. – vaughan – 2014-12-04T17:58:22.993@vaughan what is your OSX version? any special hardware? like fancy microphone or speakers or audio devices with specially drivers? – Ali – 2014-12-04T21:35:13.900
This temporarily brings back my sound. In my case, I have had audio issues ever since using a Plantronics USB headset that was provided to test Cisco Jabber. Reloading the AppleHDA kext provides temporary sound but video still lags and stutters. – Aaron – 2015-01-22T23:54:51.797
@Aron you much have some software (driver) installed that (on boot?) replaces or changes things back. Ideally they also provided you with an uninstaller that removes that faulty software/driver. – Ali – 2015-01-23T14:32:56.937
1Works. I had to kill coreaudio first, probably because a track was playing - should've stopped it first. MacBook Pro 13, late 2013, 10.10.1 – VladFr – 2015-02-05T14:22:05.283
@Ali why 'coreaudio[d]' and not just 'coreaudiod'? – dev – 2015-10-24T16:51:34.963
@dev I remember (at least at the time, I guess it was snow leopard?) there were also other processes running, that will get stuck and their name started with
coreaudio
but at least on El Capitan it looks they may not be present. – Ali – 2015-10-25T11:41:51.140@Ali but I mean from a regexp point of view, isn't
coreaudio[d]
exactly the same ascoreaudiod
? (ie a bracket expression with only one character is equivalent to that single character) – dev – 2015-10-25T11:49:20.027@dev you are correct. It must have had a
*
at the end or something. Don't really remember. Maybe got deleted in editing or something. Good catch. – Ali – 2015-10-25T11:54:13.433Using builtin speaker and this fixed when VLC caused all output to become silent. But also it caused volume control not to work. – William Entriken – 2016-07-20T20:00:30.590
Just restarting core audio solved my problem... whatever my problem was. My system just hung for 10s or so and then recovered except for sound. OS X: 10.11.5 -- but volume control doesn't work. Reloading kext's fixed it all the way. – xaxxon – 2016-08-18T10:58:49.523
10(kernel) Can't unload kext com.apple.driver.AppleHDA; classes have instances: (kernel) Kext com.apple.driver.AppleHDA class AppleHDATDMBusManager has 1 instance. (kernel) Kext com.apple.driver.AppleHDA class AppleHDATDMBusManagerCS4208 has 2 instances. Failed to unload com.apple.driver.AppleHDA - (libkern/kext) kext is in use or retained (cannot unload). – Sergei – 2016-10-01T12:09:34.510
That is great, thanks. It happens most times I do not disconnect my bluetooth headphone properly, so I have bound those commands to an alias of restartAudio in my .zsh_profile ! – swifty – 2017-02-01T19:08:21.570
Thanks @ali it finally saved me a daily restart I had for the past 3 months of my life! – Aidin – 2018-04-23T19:05:36.297
3I get the same error messages as @Sergei. After doing so, my sound is completely disabled. The icon is grayed out, the function keys don't work. I have to reboot to bring everything back. – Patrick M – 2018-08-06T23:49:14.417
7The driver loading/unloading is the only thing that worked to make the Mac detect my headphones. THANK YOU! – wizonesolutions – 2014-05-17T00:26:55.897