Yosemite install issue - File system verify or repair failed (backup help needed)

Discussion in 'OS X Yosemite (10.10)' started by FrenchPB, Oct 22, 2014.

  1. FrenchPB macrumors 6502

    Sep 15, 2005
    Hello all,

    I tried to upgrade my 2011 27" iMac from Mavericks to Yosemite but immediately received an error "File system verify or repair failed" at the start of installation following the download.

    I rebooted, held command/R to enter disk utility in order to repair the disk, but the repair failed.

    I tried the same thing using a USB drive on which I installed the recovery program, but that didn't work either.

    Every time I reboot, the Yosemite install starts again and gets me to that same message. I can still access the menu on top of the screen which gives me access to the disk utility program and to a terminal, but that's about it. From what I've read, my only solution out of that situation is to wipe the drive and recover from a backup...

    My problem is that my backup is a few months old, and I really don't want to lose my data since then. I am very worried about losing it all.

    Do you have any suggestion on what to do to save my files before starting from scratch with the installation process ?

    I have several external drives and a MacBook Air at my disposal.

    • Is there any way to make a full disk copy of my iMac harddrive to an external drive, using a program which I would start from a USB drive ?
    • Could I use the MacBook Air to access my iMac drive, through wifi, target mode, etc.) ?
    • Is it possible to change the hardrive in the iMac, then use my old one as a "slave" to access the files in it (without having to boot from that drive basically)

    I hope you guys can advise me on what to do not to lose my data. What is the easiest and most efficient way to make a full backup based on my situation ?

    Thank you very much to anyone who will take time to help me out of this bad situation.

  2. oddnendz macrumors 6502


    Feb 6, 2007
    Raleigh, NC
    I had that issue. Right now back up your files. You will have to do a clean install. It happened on 2011 17 inch Macbook Pro.

    Fix. Basically erase by zeroing out, single pass; reformat and re-install Mavericks. Then install Yosemite
  3. FrenchPB thread starter macrumors 6502

    Sep 15, 2005
    My issue is that I don't know how to backup my files from the limited options available to me at this time.

    Can I use disk utility to create a disk image on an external drive ? Would that allow me to retrive all my data after doing a clean reformat / install on my iMac ?
  4. FrenchPB thread starter macrumors 6502

    Sep 15, 2005
    Does anyone have any idea on how to back up my files ?
    I really don't know which way to go about it, my computer is completely useless right now :(
  5. lke macrumors 6502a

    Jun 19, 2009
    I have the same issue with an older imac.

    I am trying everything possible to avoid eraesing all the hard drive.

    I try to install mavericks on a usb but it was very slow because it was 2.0.

    Right now I will try to reinstall it on a SD memory card.

    I will keep you informed on how to fix this issue to avoid erasing your hard drive.
  6. FrenchPB thread starter macrumors 6502

    Sep 15, 2005
    This is the only solution I've found so far on the internet. I haven't tried it out yet, but feedback would be welcome.


    You basically install Mavericks on an external HD and boot from it, migrate data from your internal drive to the external drive, then reverse the process after doing a clean install on the internal harddrive. It all makes sense on paper, that solution was used by people having the same issue during the Mavericks upgrade.

    What do you think about it ?
  7. reBOOT918 macrumors newbie

    Nov 19, 2014
    Target Disk Mode

    I've had success using target disc mode to grab user files before erasing and reinstalling the os.
  8. HamzaAlsadr macrumors newbie

    Aug 30, 2012

    Hey did you end up finding a solution? If yes, was this it? Otherwise please let me know how did you go on about it.

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