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USB Keyboard Plugged into Monitor Often Doesn't Work

23486 Views 74 Replies Latest reply: Mar 13, 2014 5:25 AM by Ben Stanbury RSS
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Prag mac´ tic Calculating status...
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Feb 14, 2012 4:33 AM

Very often the USB keyboard plugged into the 27" Thuderbolt Display will not be recognized. It can be worked around by plugging the  USB keyboard cable directly into MacBook Pro (which always works) but the whole point is to leave the office desktop peripherals connected to the monitor when the laptop is taken away. The keyboard is a new Apple full size USB US keyboard with integral numeric pad.


17" MacBook Pro late 2011, Lion (now 10.7.3)  always up to date with all Apple software and Firmware, including all the Thunderbolt Firmware updates. The problem has been occuring since 10.7.1 or 10.7.2 (sorry, can't remember exactly what we started with but it definitely predates 10.7.3).


A temporary fix can be achieved by performing an SMC reset but the problem recurs afterwards episodically upon a subsequent instance of the computer being detached from the monitor and then reconnected.


Attachment/detachment (computer to monitor) can be either while machine is off, on, or asleep and the behaviour is the same.


Everything, all powered devices, are conencted to a new UPS with AVR and active power factor correction CyberPower CP1500PFCLCD and no events are being logged (that is, logging is active but nothing has occurred).


Thoughts, suggestions, other data about set up that I ought include?


Thanks in advance for any enlightenment.

Thunderbolt 27" Display, Mac OS X (10.7.3)
  • andrew.lee Calculating status...

    You mention issues with a USB keyboard connected to your Thunderbolt display, do you also have anything plugged into the keyboard?  If so unplug all devices from the keyboard and see if it helps.


    In my case I was inadvertently trying to draw too much power from the USB port on my keyboard (and indirectly the display).  The USB ports on your MacBook Pro can provide upto 2000 mA each, the USB ports on the Thunderbolt display can provide upto 500 mA each and the ports on the Apple USB keyboard can provide only 100 mA.  Moving my Wacom tablet from one of the USB ports on the keyboard to a separate port on the Thunderbolt display has resolved the problems I was experiencing.


    For fuller details see:





  • Will.G Calculating status...

    I have exactly the same problem with my Macbook Air and the Thunderbolt display.  Not only is the USB keyboard unrecognized when I first plug my Air into the display, but neither is the ethernet cable.  The ethernet used to work, but no more. Unplugging and replugging the keyboard fixes its problem, but the ethernet seems to be gone for good! 


    This is sounding like a serious problem.  The question is, is it a hardware problem or a software problem?


    If it's hardware, I want my money back.  This is the same sort of nonsense I had to put up with in my age-old Lenovo and Windows.  I don't expect to have to deal with it from Apple.

  • rcdeck Calculating status...

    I have this issue as well.  The only thing I have found to resolve the problem is to plugin the monitor and let it turn on, then unplug it and wait for everything to transfer back to single display and plug it back in a second time.


    It's somewhat annoying but it beats rebooting my macbook pro.


    I really hope they resolve this issue soon!

  • Akview Level 1 Level 1 (0 points)

    MBP 15" late 2011 2.2GHz  8GB ram Lion 10.7.3 with 27" TBD having same issues with loosing Apple Extended Keyboard connected to display USB but will get it back by simply unplugging and replugging.  This is an intermittent problem.  Also occurred with a mouse which I started using USB on the MPB direct in closed clam shell mood. Mouse has been working fine now.  I also have two hard drives connected to the display one USB and one Firewire.  Have also used USB on display to sync and charge iPhone all seem to work and so does keyboard for great lengths of time.  Then it will occur loss of keyboard for no apparent reason either in the middle of surfing or coming out of sleep.  Apple Care advised plugging keyboard to MBP direct to isolate that it is not a bad keyboard as well as trying update and resets.  They also advised that they are working on it.  I have updated software for display so that isn't it.  So far keyboard is doing fine connect directly to MBP and not the display as it was design for as a dock unit.  We will see and report results, just did this earlier today.


    Hopefully they will resolve issue so we can use our Thunderbolt Displays as docks as they were design to do! 

    If anyone has similar experiences do share.


  • OttawaJosh Calculating status...

    I have had the USB keyboard not working problem with both the current and last revision of the MacBook Air.  I have changed the keyboards, tried connecting direct to the MBA or through the external display.  It doesn't matter how I do it, 50% of the time (probably more) the Keyboard is not available.  The only resolution I have come to is to unplug it and plug it in again.  This issue has existed for at least 12 months (since my first MBA) and all devices are up to date on firmware.


    If anyone has an update please let me know.

  • Akview Level 1 Level 1 (0 points)

    All though I have a MBP 15" and Thunderbolt Display, I believe my problem is related to this string.  After connecting my keyboard and mouse directly to the MBP in clam shell mood I have had no problems with those items.  The HDs and iPhone I have used with the USB port on the display seem ok although it is tougher to tell if they have issues.  So my keyboard or mouse must not be the problem it must be the USB on the display.

    In my current set up I have no USBs available other that what is on the display.  So, problem is not solved.


    Last I talked to Apple Care they were investigating the issue.  Bought system Dec 2011.


    Wish I believe Apple would let me know of a firmware update on my display.



  • bdgalloway Calculating status...

    I too have the same problem -- MBP and Thunderbolt display.  When re-docking, USB keyboard won't come up.  I haven't found a reliable way to resolve the problem, although eventually I can get the keyboard to come up.  It sounds from this thread that this is a widespread problem?  Any updates from Apple?



  • arlo_j Calculating status...

    Same problem.  Keyboard + mouse plugged into display, takes a lot of unplugging + replugging to get them to recognize when 27" thunderbolt display is plugged into MBP.  I assume it's being worked on, as it's a fairly common use case.

  • Railpass Calculating status...

    Same problem.  (Thunderbolt Display + USB keyboard + late 2011 MacBook Air)

  • DaKaZ Calculating status...

    Same problem here, very annoying.  Macbook air + 27" Thunderbolt and a single USB keyboard connected to the display.  Not the way $5K of electronics is supposed to work.

  • RobbieWILM Calculating status...

    Same problem. Sometimes unplugging and replugging the keyboard into the monitor USB works, most of the time it does not. Much less frequently, the Display Ethernet isn't working. It seems ( I need to confirm 100% ) from memory that it doesn't matter whether the machine is waking from sleep or initially powering up.


    Unplugging and plugging the monitor fixes everything every time.


    This reminds me of the last time Apple released a device without even a "soft" powerswitch... that was a headache too.


    Note to apple: if you're going to release a device without a power switch you need to put more engineering and testing into the firmware ...

  • Greenieman Calculating status...

    Any resolution to this? I'm continuing to have the exact same problem as described above.

  • DaKaZ Level 1 Level 1 (0 points)

    I would like to confirm that not only is this issue still happening, I can also confirm that often the ethernet does not work as well, but it is very intermitent, maybe only 5% of the time whereas the keyboard issue is 100% of the time.  Apple, do you read these forums???  Do you not have a macbook, a thunderbolt, and a usb keyboard?  If you do, this issue would be driving your NUTS every time you go home and back to work!!!

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