I have 13-inch, early 2008 MacBook running OS X 10.7.3, and recently, the trackpad started developing some problems, so I attached an external keyboard and mouse.

It works great, except that when the computer wakes up from sleep, about 50% of the time the keyboard is unresponsive until I unplug and replug the USB connection. Any idea why this would be?

The keyboard and mouse are attached directly to the computer, not going through any USB hub.

  • Are the external keyboard and mouse plugged into another device when this happens?
    – Gigili
    Commented Feb 20, 2012 at 20:29
  • Nope. I've edited the post to clarify. Commented Feb 20, 2012 at 21:07
  • As I found out, turning off the Bluetooth might help.
    – Gigili
    Commented Feb 20, 2012 at 21:23
  • After trying everything, I plugged it into the extension cable and it worked... Commented Jan 7, 2015 at 15:26
  • Waking the Mac using the built-in keyboard makes this go away. It's annoying but a valid workaround.
    – Calahad
    Commented Oct 6, 2017 at 7:53

3 Answers 3


I sometimes have this problem with my built-in keyboard (and trackpad). It seems to be related to static electricity build-up (in me). In dry environments prone to static generation (e.g., carpeted offices, fabric-covered chairs, etc.), I always try to ground myself on something (say, a filing cabinet or a metal wall) after I sit down but before I touch the mac. If I forget and I zap the keyboard when I start to type, there's a very good chance that the keyboard and trackpad will be unresponsive. Based on my recovery action, I'm guessing that the macbook's internal USB controller has sensed the transient voltage spike as an over-current condition and has shut down (suspended) the offending devices on the associated port.

To recover the keyboard and trackpad, I either plug in an external keyboard (or vnc in via an ssh tunnel) and run the USB Prober app (part of the Developers tools, under /Developer/Applications/Utilities). Inside Prober with the Bus Probe tab selected, I then check Probe suspended devices and hit the Refresh button; my built-in keyboard and trackpad immediately start working again. My assumption is that the probe causes the suspended devices to re-negotiate their bus membership --which, if I remember the USB protocol, means that they are essentially new devices and not subject to the previous suspension -- and lets things go back to normal.

This doesn't happen often enough for me to automate the recovery, but I'm guessing there are associated system events/messages that could be used to drive an applescript-controlled probe.


Solve the problem – Your power cord must be connected to a socket with Earth (Protection Earth typical marked PE).

I have had this problem for a long time without solving the problem, besides unplugging a million times. But reading the thing about static electricity... rang a bell for me "EARTH Connection" I was only connected with 2 pin connector (Phase and Zero) I was running without protection Earth. I replaced my power cord with a 3-pin cable (Phase, Zero and PE) and connected that to a 3-pin socket. It worked right away. Why because PE eliminates static electricity besides being a protection against hazard electrical chock.


I seem to have had the same problem (USB keyboard and mouse freeze OS X when being reconnected (MacBook Air)).

I did see an error appearing in the OS utility USB Prober under the USB Logger tab (Level: '7 - Most Detail' and hit the 'Start' button).

The issue has vanished upon upgrading to OS X Mountain Lion (10.8.2).

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .