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El Capitan intermittent USB multi-media

I use a pair of Bowers & Wilkins MM-1 speakers which have worked flawlessly through several revisions of OSX.


Having just upgraded to El Capitan I now find that my Macbook Pro will often fail to recognise them. I have my speakers plugged into the USB port on a Thunderbolt display and I find that having disconnected my Macbook from the display and then returning later, it will not then detect the speakers.


A full OSX reboot solves the problem every time. If I boot with the Macbook either connected to or disconnected from the Thunderbolt and then hook everything up it will then happily find and work with the MM-1 without any issues. It seems the act of disconnecting from the Thunderbolt is causing the issue.


I've also noticed that video devices (such as the Thunderbolt camera) are also not being detected properly after a disconnect from the Thunderbolt, nor the in-built Thunderbolt audio either - all of which presumably hang off the internal USB bus.

Never seen this behaviour before and it is coincident with the El Capitan upgrade. The fault is very repeatable. A reboot always cures it. Same thing occurs if I use other Thunderbolt displays. Got to be an El Capitan bug surely?


Anyone else seeing anything similar, perhaps with other types of audio or multi-media kit?

MacBook Pro, OS X El Capitan (10.11), MM-1

Posted on Oct 5, 2015 9:58 AM

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33 replies

May 16, 2018 3:37 AM in response to bigdave1357

*********


Problem: I play any multimedia, like a video on Youtube, as soon as I stop and play again, like going to the next video or moving the play location inside the video, it fails to play gain. Reloading the page, changing browser, nothing at the app level will ever play audio.


Environment: My setup is simple: I have various audio systems connected to USB via the built-in Thunderbolt on my monitor on a 15-inch, mid 2015 MacBook Pro. Headphones, speakers... all show the same problem since upgrading to El Capitan.


Workaround: To resume I have to disconnect and reconnect the Thunderbolt cable or turn on-and-off the monitor every time the problem occurs, which is at almost every video. Disconnecting and reconnecting USB or "sudo killall VDCAssistant" does not work.


Observation: I am amazed that Apple doesn't find important to fix this issue. I'm concerned about the lost of focus on technical execution on the Mac: each new OS has few new features, most of them are features that we don't want (like the icloud, siri, facebook integrations), has serious usability issues (full screen, time machine, photos, launchpad, etc), and deep and long lasting bugs like this one (or wake from sleep).


<Edited by Host>

Oct 17, 2015 9:26 PM in response to bigdave1357

Hi Dave,


I have the exact same issue as you described. My setup is similar to yours with the MM-1 speakers connected via my external monitor's USB hub through a Thunderbolt cable. This issue started after upgrading to El Capitan. Searching through the forums, I discovered that USB audio hanging was a known issue for El Capitan during beta-testing. I hope Apple fixes this soon. I found a quicker workaround than rebooting. Disconnect the thunderbolt port, and the sound will start playing through your MB Pro speakers. It may require you to restart the application (i.e. Spotify) as well. Once you have sound through the PC speakers, you can reconnect your Thunderbolt cable and it will work as expected. I don't think it is an issue with recognising the MM-1, as they show up in Settings-->Sound even when they do not play.

Oct 18, 2015 1:14 AM in response to Ryan996

HI Ryan,


THanks for your post. Good to know it isn't just my equipment. I've not found that disconnecting helps at all. But i have found something from another post which is closely related to these symptoms and it seems to be a useful workaround.


In the terminal enter


sudo killall VDCAssistant


and and you should notice that everything starts working again, not just the MM-1. I've used this a couple of times and just verified it again now. Seems to work. I hope this is useful for you. Clearly Apple have got some work to do in this area.

Oct 19, 2015 8:04 AM in response to bigdave1357

I just upgraded to El Capitan 2 days ago. I have a Mid 2012 Macbook Pro. Running a Samsung monitor through Thunderbolt as well as an Acer monitor through a USB 2.0-VGA adapter connected through a USB hub. Also have Logitech speakers w/sub connected through headphone, Logitech wireless mouse and Mac wired keyboard. All those peripherals work EXCEPT the Acer monitor. It displays but is off color and has lines displaying vertically throughout. As noted on a different post, if I take a screen-shot from that monitor, it looks fine. Tried all the suggestions on other posts, nothing fixed the issue. Have discontinued use of the Acer till I find a fix. (SIGH-Just got that set up together less than 2 weeks ago...hoping for a quick fix, do not want to have to downgrade back to Yosemite---trifling)

Oct 22, 2015 12:47 PM in response to bigdave1357

Hi Dave,


I have the same issue as you described, so you are not alone. My setup is very similar to yours. I have a MM-1 speaker connected to my LG 34UM95 monitor with USB, and the my monitor and mac is connected with Thunderbolt.


I have no problems with this setup, before upgrading to El Capitan.


I noticed when the problem occurs, video on youtube won't start.


I hope we are able to find a solution to this problem.


MacBook Pro, OS X El Capitan (10.11.1), MM-1, LG 34UM95

Oct 22, 2015 12:59 PM in response to ftoft

Hi ftoft,


You're video won't start playing because the auto system is trying to route audio to the MM-1 speakers and cannot, because of the what I suspect is the USB/audio related fault.

You will probably find that if you try


sudo killall VDCAssistant


the MM-1 (and your other USB gear) comes back to life. Try restarting your YouTube video and you might find that it works.

Oct 22, 2015 1:30 PM in response to bigdave1357

Hi again,


It look like i don't have the VDCAssistant process running on my system.

When i try to run 'sudo killall VDCAssistant' it says 'No matching processes were found' :/


I have for some weeks tried to connected my speakers direct to the USB on my mac. But still have my mouse and keyboard connected to my monitor. The it works fine. But not a optimal solution.

Oct 26, 2015 11:01 AM in response to bigdave1357

Although the sudo killall VDCAssistant was working for me as a temporary fix I've now updated to OSX 10.11.1 and things are worse.

I was hoping that this patch would fix the problem entirely.

I now find that it has not fixed the problem and has prevented the workaround from working.


I am now having to reboot my Macbook every time I disconnect from a Thunderbolt.

Nov 2, 2015 4:13 AM in response to bigdave1357

Hi. I have something similar. Cameras hat I connect to my computer when downloading are no longer detected by the applications I use to do the importing. If I put the cards in a card reader and then connect, I can see the cards on my desktop but the applications I use will not detect the card or the camera.


Strangely, the Photos app does launch when connecting a camera so I'm not convinced it's a hardware fault but something in El Capitan that is causing USB connected cameras not to be detected by third party apps.


There do seem to be a lot of USB related issues being discussed on these forums currently.


Cliff

Dec 14, 2015 11:30 AM in response to ftoft

I'm having the exact same issue with my 34UM95 monitor and B&W MM-1's. I've also updated my speaker's firmware and it didn't help at all.


Have you guys tried opening a support ticket with B&W? I did when I first started running into this issue and after a few back and forth emails, they gave me the whole "We'll let our engineers know" brushoff. We might get some traction if everyone lets them know they are running into issues.

Dec 14, 2015 12:40 PM in response to bigdave1357

I upgraded to 10.11.2 pretty much as soon as it became available in the UK and I've been monitoring the situation since then. I've held off making a post to make sure that the findings I have are solid. I can report that since the upgrade the whole Thunderbolt / USB system seems more robust. I've performed a lot of disconnect / connects since then and I have not had a single problem with the MM-1 not being recognised.


I think there are still some USB issues - for example I'm pretty sure I've seen the slow / not charging problem when connecting iPad or iPhone, but overall I would say that 10.11.2 seems quite a bit better and my original problem seems to have gone away.


I had already upgraded my MM-1 to version 3 of the firmware quite some time ago so I very much doubt if this is an MM-1 problem, after seeing the improvements delivered by 10.11.2. That said, a couple of you are clearly still suffering so maybe 10.11.2 doesn't fix all the issues in all circumstances.


In my opinion El Capitan 10.11.2 USB is still somewhat problematic but much better. Since this issue is not solved for everyone I won't mark the problem as solved.

Dec 20, 2015 11:37 AM in response to bigdave1357

I'm having this same issue with an Audioengine d3 DAC connected through an LG 34UM95 over thunderbolt. Also on 10.11.2. Didn't have this problem with an Apple thunderbolt display on 10.11.2 with the DAC connected through that.


What is especially odd is the way the problem initially manifested: I was unable to stream any video - it seemed like amazon streaming, netflix, youtube, were all having connectivity problems - until I switched to internal audio and tried again. I also couldn't play any tracks in iTunes. If I plug the DAC into the Macbook Pro (15" late 2013 nvidia) directly, it's fine, or if I reboot and don't disconnect anything, it seems to work.


This is really frustrating, it's making me consider rolling back to 10.10.

El Capitan intermittent USB multi-media

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