Q: USB Audio Device Not Showing in "Audio Devices" (M-Audio Venom Synth)

Saturday I connected a M-Audio Venom Synth to my iMac, which is running El Capitan 10.11.1 (mid-2011 27".)

This device includes an Audio Interface, and it connects over USB.

Initially.. it worked. And I could confirm this as:

1. When I opened up the "Audio Midi Setup" I could see in the "Audio Devices," beneath the usual suspects ("Built-in Microphone" etc) a NEW entry for "Venom" was there. But I can't recall exactly what it said now, only that the device was listed there.

2. When I opened Logic Pro X (latest version .. 10.2 I think it is) I could add an "Audio" track and select my Venom as an input. And sure enough, the crazy sounds from the synth were routed in to Logic. Nice.

However..

After powering off the Venom device (and going to bed) I awoke to find a different story. Feeling inspired, I switch on the Venom, jumped into Logic Pro, but was sad to see that I could no longer select the Venom as an audio input.

And when I checked the "Audio Midi Setup" utility, and looked at the "Audio Devices" window ... the Venom entry was no longer there. Argh!

Since then, I have spent hours crawling through forums for answers. But nothing I've tried has worked.

What I've tried:

1. Multiple resets

2. Disconnecting every USB device except the Venom

3. Connecting the Venom to every USB port

4. Did the "SMC" and "NVRAM" / "PRAM" reset process

5. M-Audio provides drivers for Mac OS X, but it only goes up to 10.10 — but they state that the Venom is a Core Audio complaint device, and doesn't need drivers to work on Mac OS X. Well, I installed the drivers anyway because I'm trying all I can...

6. I reinstalled OS X!!! Hoping maybe a core audio type driver was corrupt and this would fix it.. nope.

7. Random things like removing the com.apple.audio.devicesettings.plist and com.apple.audio.systemsettings.plist files from the Library/Preferences/Audio/ folder and restarting the machine and seeing if that fixes it..nope.

This is so frustrating. I feel sick to be honest because of all the things I've tried ... AND THE THING WORKED THE FIRST TIME! So I know this device works...

What can I do?

I really hope somebody can help.

Cheers,

Jordan