13 Replies Latest reply: Feb 2, 2013 12:35 PM by Eric Root
beanwalls Level 1 (0 points)

I've not changed anything about my Macbook Pro (13" early 2011) except upgrade to Mountain Lion (10.8.2) and now when I plug in my USB hub (which only has my keyboard, mouse and printer connected to it) the computer freezes completely and I have to press and hold the power button to restart it. If it doesn't do that, then it just doesn't recognise that the USB has been plugged in at all.


Is this an issue with the USB port or something else? I still have AppleCare so will take it to an Apple Store if I can't find out how to solve this problem myself. Anyone had this issue and found a solution?



MacBook Pro, OS X Mountain Lion (10.8.2)
  • beanwalls Level 1 (0 points)

    OK so I've done some searching on here and tried booting in SAFE MODE and then restarting.


    This has changed the problem but not solved it - now when I plug into the nearest USB port (the nearest if I'm looking at the screen) then all is fine and the printer is recognised, but if I plug into the furthest away USB port then the printer is not recognised at all.


    There is no freezing now it seems but the furthest USB port doesn't recognise the printer, or maybe it's the USB hub it's not recognising...


    Any advice out there?



  • Topher Kessler Level 6 (9,865 points)

    Try bypassing the hub and attaching only your keyboard to the system directly. Then see if the problem still occurs.

  • beanwalls Level 1 (0 points)

    Thanks for the reply.


    I just tried plugging the printer directly into the USB port on my Mac, and I get the same problem - the nearest USB port recognises the printer but the furthest away doesn't.


    Does this mean I have a faulty USB port?

  • Topher Kessler Level 6 (9,865 points)

    I'm trying to assess that, but in order to do so it would help if you tried plugging a mouse or keyboard into the problematic slots to see if they work with that device. If not then it suggests a port problem, in which case try this same routine when booted to the Recovery HD partition (hold Command-R at startup to boot to this volume). Then try the keyboard/mouse in the different slots again.


    These exercises will help determine if the problem is driver-based, or a problem in hardware.

  • beanwalls Level 1 (0 points)

    Got it.


    OK. I plugged my Apple keyboard directing into the rear USB and it didn't work, I then plugged it into the front USB (thinking it would work as before) but instead I get an error message saying one of your USB devices is drawing too much power and has been disabled. The keyboard was the only device plugged in so it must have that.


    I'm baffled now!

  • Topher Kessler Level 6 (9,865 points)

    Did you also try this when booted to the Recovery HD volume? If not then give this a try. In addition, while troubleshooting unplug all USB devices (includeing the keyboard) and try with another device such as only the mouse, which should allow you to move the cursor on screen. What you've done so far is only half of the picture, and doing this with the mouse both in normal boot and when booted to the Recovery HD partition would help determine what the problem is.


    It is sounding like the issue is not with the printer and instead is with your computer, so hopefully its just a software configuration snafu, but it could be a problem with hardware.


    If you find the mouse will not properly work in any port when booted to the Recovery HD partition, then run the Apple Hardware Test suite (see here: http://reviews.cnet.com/8301-13727_7-57352461-263/how-to-invoke-and-interpret-th e-apple-hardware-tests/, but do not run the "extended" test) and see if they bring up any problems. If so then write them down and post what they are here.

  • beanwalls Level 1 (0 points)

    Sorry for slow reply. We've got a time difference and I went to sleep.


    I didn;t try it in the Recovery HD Volume as when I did the Command-R thing I got nervous as it seemed as though it was going to reinstall the OS and I haven't backed up to Time Machine in the last couple of weeks and don't want to lose work. Can I get into Recovery mode without doing that? If so, which option do I choose?


    And then - if the keyboard and/or mouse work fine in recovery mode then should I still do the Hardware Test thing?


    Apologies for all the questions. You are being really helpful so thanks.

  • beanwalls Level 1 (0 points)

    So I went back into the Recovery HD mode and tested the mouse on that first screen you get to. It worked fine in both USB ports.


    I then restarted as normal and tested the mouse again, and as with the printer, it works in the nearest USB port but not in the furthest away.


    I'll run the hardware test now and post up the results.



  • beanwalls Level 1 (0 points)

    Ran the hardware test and it found no issues at all.


    I should be pleased I guess but am actually disappointed!

  • Topher Kessler Level 6 (9,865 points)

    This shows the problem is based in software and not a hardware problem. Have you installed any driver software for USB devices, or do you have any other input managing software for your system? If so then try uninstalling them to see if the problem persists.


    Does the issue happen if you boot the system into Safe Mode (hold the Shift key at startup to get into Safe mode--you will see a progress bar appear at bootup when this moder is activated).

  • beanwalls Level 1 (0 points)

    As far as I'm aware there is no driver software for USB devices installed. I wouldn't know what I would need anything like that for...


    I just booted in safe mode and the mouse works fine in both USB ports in that mode too.

  • beanwalls Level 1 (0 points)

    Are you out of ideas? Or did you just get busy?

    I guess I should think about getting myself to the Apple Store.. unless anyone else has a way to solve this?

  • Eric Root Level 9 (50,244 points)

    Here is a troubleshooting article:




    Since you still have Apple Care, if nothing in the article helps (which wouldn't surprise me), I'd take the computer to the Apple store and let them sort it out.