I just plugged a USB hard drive into my MacBook Air and for some reason it immediately went into sleep mode (it also stopped the music I was playing on iTunes). What could be the issue? Is it something I should worry about? I just tried to plug it in again but nothing weird happened, the drive works fine.


This can happen if for some reason it pulls more power then the computer can handle. If this happens only once, I wouldn't worry about it too much, however if it becomes a repeat issue, it could mean there is a problem with the power regulation, the USB port, or both.

  • That shouldn't (not can't) happen: OS X is supposed to simply refuse to provide power for it and provide a "To prevent damaging your computer, the USB device drawing too much power has been disabled. Other devices may have also been disabled. When you disconnect the device drawing too much power, your other USB devices will be enabled again." message.
    – JMY1000
    Mar 23 '16 at 3:33
  • 1
    Agreed, but the computer also shouldn't go into sleep mode just because a device was connected to it.
    – iWill
    Mar 26 '16 at 3:15

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