Note on which bus is this external USB port. to refresh the USB connection information. To check this hidden cabling, just use your external mouse.Ĭonnect it on port nearest from the front. This value might be different depending on the USB port available outside and what is already connected on it internally.Īs a basic simple rule, avoid the external USB port which is on the bus where is connected the FaceTime HD camera ( Current Required (mA) = 500 mA).įor example, on a MacBook Pro, I discovered through trials that my FaceTime HD camera is on the bus with the USB external port nearest from the front. Verify that the sum of the Current Required (mA) of all the equipmentsĬonnected to the same internal USB hub don't exceed the Current Available (mA) for the hub. Include this screen capture within your OQ (original question).

Make a screen capture: command shift 4, space, select the USB map window and click. Lower part of the window to have a complete vue of all your USB equipments. Select the USB bus where is connected your USB hub, and enlarge the Open the  > About This Mac > System Report., Just wondering if there are any suggestions or recommendations as to how I can troubleshoot or resolve this?įollowing are screenshots of the USB map (two separate screenshots as the contents of the USB 3.0 Bus details page didn't fit in one screen)ĭisclaimer: this is an answer under construction. It's very frustrating and inefficient for my workflow.

To reconnect them, bizarrely, i seem to need to unplug and replug each device in 3 times specifically. But they also sometimes disconnect without this trigger. This USB hub is connected to its power adaptor.įrom memory this problem also existed before El Capitan update.įor work I use Microsoft Lync for Mac, and I sometimes notice than when a new instant message arrives, my keyboard, mouse and headset will disconnect. I bought this one in the hope it might resolve this problem, but it didn't. I'm currently using a Targus 7 port USB 3 hub ( ) but this problem existed when I was using an older USB hub. For a long while now I've experienced USB devices intermittently disconnecting on my Macbook Pro Retina 2012 (El Capitan 10.11.2).

Mac powerbook pro usb intermitten