External hard drive not reading, and only being powered on 1 of 2 USB slots (right)

Discussion in 'Mac Basics and Help' started by Yumid, Jul 8, 2014.

  1. Yumid macrumors member

    May 11, 2014
    So I have a late 2013 15' Macbook Pro Retina with a 512gb SSD.

    I just bought a Western Digital 7200rpm hard drive + enclosure today to back up my work and work off of a an external hard drive.

    Im new to using external drives so this may be a simple solution but here is the problem.

    1.)I put the hard drive into the enclosure, screwed it back on, and tried plugging it into the LEFT usb slot on my macbook pro. Nothing happened, so I thought maybe I put it into the enclosure wrong(which scared me because there is only really one way it fits) But I tried the right side of my macbook on that USB slot and the drive powered up so at least I know I didnt break it by installing it into the enclosure wrong.

    2.)Now when I plug it into the right side a popup comes up that says "The disk you inserted was not readable by this computer" and it gives me an option to Initialize, Ignore, Or Eject. From this point on I am lost.

    I clicked initialize but none of that means anything to me. I will also be using this drive on school computers which are PCs. My home system is a mac. So I need to format the drive to work on both.


    a.)Why is my drive powering on the right side usb but not the left? Will the drive even plug into my USB 3.0 powered USB hub I ordered?

    b.)How do i proceed from that pop up?

    c.)Do I need to format it from a PC as exfat so it works better on both of the systems I will be using it on? I think I remember having to do that with an old Western Digital Ultra Passport I was using before. But it wasn't 7200 so I needed a new one.
  2. Fishrrman macrumors G5


    Feb 20, 2009
    Does the drive enclosure have a port for an external "power supply brick"?

    Sounds like the drive may not be receiving enough power to spin up and mount (from a single USB port).

    What is the capacity of the drive?

    That could be a factor.

    You may need either:
    1. an external power supply
    2. a USB "Y-cable" (with one USB plug on one end, and two plugs on the other end).
  3. satcomer macrumors 603


    Feb 19, 2008
    The Finger Lakes Region
    Wow people have not heard of formatting for a computer. Most far East manufactures still use Windows XP so they pre-format NTFS for windows only computers so most mac use /Applications/Utilities/Disk Utility.app to format new external drives so OS X can use that drive. So follow these steps since you failed to realize this and messed it up.

    1. Disconnect any drive from you Mac.

    2. Restart your Mac while performing a Reset NVRAM/PRAM.

    3. Upon the restart plug the drive back in and cancel any pop-up. Then go to the folder /Applications/Utilities/ and launch the application DiskUtility.app.

    4. Using Disk Utility and in there highlight your external and in the right hand window click on the mini-tab 'Erase' and the drive and format it HFS Extended Journaled. Let it finished then it mounts back on you desktop and then quit Disk Utility.

    5. Then launch System Preferences->Time Machine and use that to setup Time Machine on that external.

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