Previous 1 2 Next 16 Replies Latest reply: Jan 2, 2013 1:58 PM by benkeenan2005
alexxedge Level 1 (0 points)

I bought a new Western Digital MyBook 2TB external harddrive today. I've recently updated to Mountain Lion and for some reason the external won't let me access it to start backing up data. I've tried to format it and I get an error that reads "One of the volumes on the device is busy and cannot be dismounted." I've run disk utility to verify the disk and "the volume MyBook appears to be ok". Is anyone else having this problem? I have another External hard drive that is the exact same that I had purchased last year, before updated to Lion, and it still works just fine even after updating to Mountain Lion. I can't even tell if the WD Smartware is up to date, because when I try to install the newest Smartware that is on the hard drive is runs....but never finishes. I always have to force quit the installer because it never does anything. I've let it sit for about a half hour with no change.


Sorry if this issue has already been posted. I've seen other discussions of people having problems with their WD hard drives not mounting or being recognized at all by their machine, but I feel this is a little different.

iMac (24-inch Early 2009), OS X Mountain Lion, Western Digital 2tb MyBook exteranl
  • William Lloyd Level 7 (21,040 points)

    Where did you buy it?


    Before you start backing up to it, if it's brand new I would suggest reformatting it via Disk Utility.  You'll want to ensure you format it as Mac OS X Extended (Journaled).  Chances are it came formatted as FAT32 which is a very old, archaic PC format that doesn't support everything OS X needs to back up properly.

  • alexxedge Level 1 (0 points)

    Hey William,


    It was actually bought for me as a birthday present. It came from BestBuy and it's supposed to be formatted for Mac. Well, at least it's supposed to be, because that's what it says on the front of the box.


    But, with that being said, how would I go about reformatting it via Disk Utility?



  • William Lloyd Level 7 (21,040 points)

    Open Disk Uitlity, then click on the drive in the sidebar.  Click where it says 2 TB Western Digital Media and then click the "Erase" tab at right.  Ensure the format is set to Mac OS X Extended (Journaled) and it should reformat it.


    Also, check the "Partition" tab to the right of the "Erase" tab.  At the very bottom of the window it should say Partion Map Scheme: GUID Partition Table.  If it says something else let me know.

  • alexxedge Level 1 (0 points)

    Excellent. Thanks for the help. This definitely did the trick!

  • Shootist007 Level 6 (16,660 points)

    Actually your best option is to select the Disk Name, Go to the Partition tab and select One partition from the drop down in the Partition Layout area. Give it a name, whatever you like, Format it Mac Extended (Journaled) with a Partition Table of GUID (that is in the Options section, options button at the bottom of the Partition Layout area).


    Most of these WD drives come with some software, that you do Not need and should Not install, that may be on it's own partition. So Re-Partitioning it as One Partition gets rid of all that.


    You can then, if you like, make another or 2 or 3 partitions for various things. I have one of those drive and have it partitioned for TM backups of both Mt Lion and Lion, keeping those TM backups separate, and then 2 or 3 other partitions for clones, of currently install OS X versions and or installs of older OS X versions.

  • MosesMoses Level 1 (0 points)

    Hello William,

    I have a similar situation to what opened this chain. I am taking my 1TB WD Ext HDD 1021 Media, drive, previously dedicated to my old powerbook and now dedicating it to new MacBook Pro. I was going to follow your directions but paused when I saw the Participation Map Scheme was Apple Partition Map. Do i need to specifically change this during the erase? Thanks for any guidance.

  • mattmanmcc Level 1 (0 points)

    I have the same problem with my hard drive (same make and model), except that the hard drive's format is already Mac OS Extended (Journaled) and not FAT32. Should I do the same thing as described above, or should I do something different?

  • Shootist007 Level 6 (16,660 points)

    By default all WD external drives are formatted for the Windows Operating system and have  NTFS format. That is unless it is Specifically specified as for a Mac computer. That format, Windows NTFS, will not work on a Mac although OS X can Read NTFS formatted drives but it can not Write to them.


    You need to use Disk Utilty and either Erase or Partition the drive with a format of Mac Extended (Journaled).


    I suggest Re-Partitioning as One Partition and in the process make sure the Partition Table is set to GUID..

  • mattmanmcc Level 1 (0 points)

    The hard drive is specifically made for Mac and it's already formatted af Mac OS Extended (Journaled). Should I just reformat it?

    Screen Shot 2012-12-28 at 7.31.36 PM.jpgScreen Shot 2012-12-28 at 7.30.52 PM.jpg

  • Shootist007 Level 6 (16,660 points)

    I would and I Would Not use any WD software to do it. Select the TOP name of the disk in Disk Utility, "2TB WD My Book 11A.." and go to the Partition tab and Re-Partition it As One Partition.

  • mattmanmcc Level 1 (0 points)

    Now what?

  • Shootist007 Level 6 (16,660 points)

    If you are in the partition section the middle area that shows the partitions just at the top of that there is a box with a down arrow, click on that and select Once partition. Then Under the partiton windows there is an Options button, click that and make sure it is set to GUID then OK and close that dialog box. Then click the Apply button.

  • mattmanmcc Level 1 (0 points)

    I did that and I opened up the hard drive folder and it's empty, none of the stuff that was already there at the beginning. Is that supposed to happen?

  • Shootist007 Level 6 (16,660 points)

    Yes that is Supposed to happen. I have used many WD drive on both Mac and PC and the one thing you NEVER want to do is Install any software that comes with the drive, whether for Windows or for Mac OS X. There is NO need for any WD software and it has been my experience with helping others that when that WD software is installed it only creates problems.

    By Re-Partitioning the drive as one partition you have now wiped all traces of whatever WD put on that drive. It is not needed or wanted, IMHO.


    You should now have no problems copying files to it and or using it as a Time Machine backup drive or doing both.


    Good Luck and Best Wishes. HAPPY New Year.

    mattmanmcc wrote:


    I did that and I opened up the hard drive folder and it's empty, none of the stuff that was already there at the beginning. Is that supposed to happen?

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