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Not recognizing external HD...problem with USB ports

3213 Views 6 Replies Latest reply: Sep 18, 2013 11:58 AM by cyndielouwho RSS
TKrupp Calculating status...
Currently Being Moderated
Mar 28, 2013 8:17 PM

I just got my new 27" 3.4ghz i7 iMac today, and I've been trying to transfer everything over from my PC VIA external hardrive; however, my iMac is not showing that an external HD is connected.  I initially tried connecting 2 USB powered external drives into all 4 USB ports with no luck.  The third external hardrive I tried is powered by an AC adapter, and that was recognized by only USB ports 3 and 4, ports 1 and 2 did not recognize it.


Could there be a problem with my USB ports?  Seeing as only ports 3 and 4 picked up the AC powered hardrive, and none picked up the USB powered external drives.  All the USB ports, however, work with my iPhone, etc.


I have the options ticked in Finder preferences to show Hard Disks and External Disks on the Desktop.  I also looked in the Disk Utility and the only external drive that showed up was the AC powered drive plugged in ports 3 and 4.

iMac (27-inch, Late 2012), OS X Mountain Lion (10.8.3)
  • Eric Ross Level 6 Level 6 (11,650 points)
    Currently Being Moderated
    Mar 28, 2013 8:41 PM (in response to TKrupp)

    Are you using Migration Assistant to transfer your data?  If so then take a look at this link,


    Try launching disk utility and see if the drives show up, I am thinking the drive is formatted NTFS,

  • cyndielouwho Calculating status...

    I had the same problem. I emailed ioSafe and they called me back. The new macs have a power saving chip so the ioSafe is drawing to much power. You will need to plug in both usb ends on the y cable it came with  into both usb ports on your mac. You can send ioSafe your address and they will send you the new cable for use with the new macs. I hope this helps it took me 5 hours to figure it out!

  • cyndielouwho Level 1 Level 1 (10 points)
    Currently Being Moderated
    Sep 18, 2013 11:58 AM (in response to TKrupp)

    Sorry this took so long for me to see. That's great! Glad you got your cable!!


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