Questions & Answers

My AudioBox Series interface does not stay connected to my Mac OS X 10.11 system.

+1 vote
asked Dec 12, 2015 in AudioBox USB by AlexTinsley (925,190 points)
I cannot reliably connect my iTwo to my 13" Retina MBP (2013) running Yosemite and 8GB of RAM. After selecting the iTwo as my audio input/output device, it works for less than 30 seconds before I hear two soft clicks and then my MBP says that "the CoreAudio device is no longer available." MIDI continues to work without any problems. It is only the CoreAudio connection that is flakey.

- I have tried different USB ports and different USB cables
- I have tried both GarageBand and Ableton Live 8
- I have tried disconnecting everything else (MIDI, etc.) except for the USB cable and a set of headphones

So far, the iTwo seems to work with my 2014 iMac Retina with El Capitan so the problem exists only with the MBP.

2 Answers

0 votes
answered Mar 23, 2016 by matthewgorman (52,060 points)
Best answer

There has been an update to el capitan that fixes USB connectivity. It is recommended that usb device users install this update to 10.11.4.

+1 vote
answered Dec 12, 2015 by AlexTinsley (925,190 points)
We are seeing this problem sporadically with customers like yourself that have updated from a previous Mac OS X version to 10.11. Apple removed Kernel functions that affected more than just our products. Any software that relied on kernel operations is most likely causing the problem and needs to be removed from your system.

This issue stems from some older software on your system that is not compatible with 10.11 that is causing the Core Audio Driver to reset, when it does, the iTwo (or any USB Audio interface) will fall of the bus, when the bus resets, the audio comes back (then the process repeats).

This is not a Presonus problem as Presonus does not make the device driver for OS X, this is an apple product. We have notified apple of the issue so they are aware of it. You may want to contact Apple.

You'll need to check with all the companies that you have 3rd party software installed for to make sure their applications support El Capitan. Some companies still do not recommend upgrading to 10.11 as not everyone has updates for it yet.

To find the offending process or application that is crashing the audio bus, open up your System Report, and scroll down to Logs under Hardware in the left column, and look at the Apple System Log to see what applications are failing. You might get lucky and find the offending application. If this takes too much time you may want to consider a reinstall of your OS.

I don't mean going back to 10.10 and upgrading again, I mean use Disk Utility to create a new disk partition and Install El Capitan fresh (takes about 30 minutes). If you do this problem will not occur. You will need to reinstall all your software however you'll be getting the latest versions that work with 10.11.