This is extremely annoying. 2009 MacBook Pro running OSX 10.7.5. I have an external hard drive connected via USB for Time Machine purposes. This device, and anything else connected via USB, frequently accidentally ejects with the slightest disturbance such as when I brush against the USB cable. It's very extremely annoying. The trouble doesn't come up as often with devices without a cable like flash drives, but sometimes it happens. It happens very frequently with devices connected via a cable. What is going on?

  • Try cleaning the plugs on USA both sides, using NON metallic objects (like a toothbrush). Or...Insert a USB extender cable! You have more than one USB, do they all do the same? – Jadav Mar 29 '13 at 12:45
  • thanks for your reply. Yes they both do the same and most noticeable with devices that uses a USB cable. Both USB ports and multiple USB devices, so it's difficult for me to narrow down the problem. Sorry I'm not sure what you mean by "USA both sides." Is that a typo and supposed to be "USB"? – rabbid Mar 31 '13 at 10:38
  • I stumbled on to your question in my search. Since you experience the same problem on both USB plugs with different USB cables! Sounds like your problem is not external (not the USB plugs or cables) but your USB controller. First Check it with: "About This Mac..." under the apple icon in the upper left of the screen, selecting "More Info + system report..." and "USB" under the "Hardware" list, to get information. This is not a test it is just a information page. Updating or reinstalling your OS eliminates the issue in most cases. If you want to try the build in Hardware test, follow this instr – Common-Courtesy Mar 31 '13 at 11:33

You either have a bad USB cable or a bad USB jack (either on external devices or Mac). I would start by replacing the USB cable on the external hard drive. If that does not work then your USB jack will most likely need to be looked at by an Apple repair center.

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