MacBook Air USB 3.0 Port Question/Problem

Discussion in 'MacBook Air' started by dlbmacfan, Jun 18, 2012.

  1. dlbmacfan macrumors regular

    Jul 20, 2011
    I have a new MBA that supports USB 3.0, and I just purchased a USB 3.0 external drive. The drive works great when I plug it into the USB port next to the MagSafe 2 port, but it's not recognized when I plug it into the USB port next to the Thunderbolt port. The power light does light up on the drive, but Finder can't see the drive. Any ideas on why this might be happening? Is there a difference between the two USB ports?
  2. mitty macrumors regular

    May 21, 2010
    Not that I can see. I plugged in a USB 3.0 Seagate drive (1.5TB) and the USB port on the right side powers it fine.
  3. angemon89 macrumors 68000


    Feb 5, 2008
    The place where Apple designs stuff
    There shouldn't be a difference. Can you see the drive in disk utility?

    I plug my MyPassport USB 3 drive into both sides fine.
  4. jgc macrumors regular

    Feb 21, 2012
    I have one possible but unlikely reason. Typically the USB port(s) closest to the processor on a computer will provide a bit more power/speed than USB port(s) that are further. So if your processor is closer to the left side of your laptop, the left side port(s) will provide a bit more power. The difference shouldn't be big however if you're using a USB drive that is powered via USB, it could be that the slight difference in power is just enough to not fully recognize your drive on one side. It may provide just enough power to turn it on but not enough to mount it and make it available for transfer.
  5. jamesvdm macrumors regular


    Mar 28, 2011
    Perth, Australia
    Clearly your USB port is faulty. Return the laptop.

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