Old Macintosh HD not recognized by iMac

Discussion in 'iMac' started by TheGuru, Jul 31, 2015.

  1. TheGuru macrumors newbie

    Jul 31, 2015
    Hello folks!
    This is my 1st post in this forum and would like some assistance.
    Apple had replaced a 3TB HD on my iMac and I currently have plugged in the old HD into a USB 3.0 enclosure which is Mac compatible. The issue is iMac recognizes the External hard drive as 'Macintosh HD' but I am not able to view the content on the HD.

    This is the error I am seeing when I click on the HD in Disk Utility program

    "This Fusion Drive is missing a disk. Would you like to rebuild this Fusion Drive?"

    Any suggestion how I can view data on this HD or do I need to Rebuild the disk which will erase all the data on the drive.

    Thank you.
  2. matreya macrumors 65816


    Nov 14, 2009
    Well, normally, people would already have all their data backed up to at least a time machine backup...

    I've come across some command-line voodoo that purports to fix a fusion volume, but I would be very wary of following them.

    I also wouldn't trust re-using a defective drive, a new one is a better investment.
  3. Fishrrman macrumors G5


    Feb 20, 2009
    We need more information.

    You wrote above:
    "Apple had replaced a 3TB HD on my iMac"

    Did you buy the iMac with a fusion drive as standard equipment?
    Did you subsequently experience a drive failure?
    Did they put a -fresh- 3tb hard drive into the iMac, and then give you the old drive back?

    I'm thinking that if the iMac came originally with a 3tb fusion drive (which is composed of a 128gb SSD and a 3tb HDD), and if Apple replaced the 3tb HDD, and if "the old one" is what you now "have in your hand" -- that Disk Utility is still "seeing it" as representing "one-half" of a fusion drive and will try to "re-integrate" it with other drives in your Mac.

    If that's the case, you DON'T want Disk Utility to "rebuild the fusion drive".
    You may already have a working fusion drive setup -in- the iMac.

    Again, we need more information.

    Instead, you want to re-initialize the 3tb "drive in your hand" to HFS+ and use it as a "standalone" drive...

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