Is my iMac completely screwed?

Discussion in 'iMac' started by clauditorium, Dec 28, 2016.

  1. clauditorium macrumors newbie

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    Aug 8, 2010
    #1
    Here is the sequence of events:

    1. The graphics card broke on my iMac. Unfortunately, it’s hard to find a new one for my 2010 model. So I decided I would get a new computer and sell this one for parts. At this point, I could only start the computer in safe mode.

    2. I wiped my hard drive, using the slowest, most thorough method.

    3. Now I can’t start the computer in safe mode anymore. It gets stuck on the screen in the attached photo.

    4. I am able to start it in Internet Recovery Mode. I run First Aid and get this message: "First Aid found corruption that needs to be repaired. To repair the startup volume, run First Aid from Recovery." But… that’s what I just did, and no repair happened. The computer also won’t allow the OS to be reinstalled from Recovery Mode. I got two different messages on two separate attempts: "Source volume format on device "/dev/disk1" is not valid for restoring" and "Checksum failed. Expected 5F81F5A3 but got 83373F4C. Could not restore. Invalid argument.".

    5. I made a USB Install disk and tried booting the computer from that, but it doesn’t recognize it; it only gives me my hard drive as an option to boot from. And yes, I’m plugging the USB directly into the computer, not a hub. I also tried booting while holding down the C key, and got the screen in the attached photo.

    6. I also tried resetting the PRAM. The Mac chime came twice, as it's supposed to, but then got stuck on that same screen in the attached photo.

    7. Another part of the message I got from running First Aid: "Problems were found with the partition map which might prevent booting." Anyone know if I can do anything about that?
     

    Attached Files:

  2. kschendel macrumors 6502a

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    Dec 9, 2014
    #2
    You don't say how you wiped the hard drive, but I presume that you wiped out the filesystem at least, and probably the partition map as well. So, not only is there nothing to boot from, there's no partitioning to restore to. Do you have an install DVD? (I assume the 2010's still had internal DVD?) You need to run something that will be able to reformat, partition, and install a filesystem onto the disk. I don't know if you can do that with Internet Recovery, as I've never used it myself.
     
  3. clauditorium thread starter macrumors newbie

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    Aug 8, 2010
    #3
    Unfortunately, this iMac did not come with install disks.

    I used the erase function after starting the computer in Internet Restore mode. It gives you the option of different levels of thoroughness. I picked the highest level.

    --- Post Merged, Dec 28, 2016 ---
    Should I attempt to partition the drive? Disk Utility gives me that option. If the answer is yes, though, I need help, because once you click "Partition", it gives you options I don't know how to choose...

     
  4. kschendel macrumors 6502a

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    Dec 9, 2014
    #4
    You only need a single partition. If it asks something about MBR vs GUID (I don't recall), GUID is the better choice in this situation. Ask it to install a journaled HFS+ filesystem. You don't need case sensitivity or encryption, if either option is offered.
     
  5. Fishrrman macrumors G4

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    Feb 20, 2009
    #5
    1. Power all the way down to off.
    2. Reboot from the USB installer drive
    3. Once booted, go to Disk Utility
    4. NOW re-initialize the internal drive
    5. Before you quit DU, run the "repair disk" function on the internal drive.
    6. What kind of report do you get? Is it a good one?
    7. If you do get a good report, REPEAT the repair disk function FIVE TIMES in succession.
    8. Do you get a good report each and EVERY time?
    9. If so, NOW go to the Installer and try installing the OS once more.
     
  6. clauditorium thread starter macrumors newbie

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    Aug 8, 2010
    #6
    Unfortunately, as I said in my post, it won't reboot from the USB installer drive. The only way I can do anything on the computer now is by turning it on in Internet Restore Mode. And if I try to restart from there using the USB drive, it doesn't show up as an option.

     
  7. clauditorium thread starter macrumors newbie

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    Aug 8, 2010
    #7
    Pardon my ignorance, but for partitioning, I select the physical disk, right?
    Once I click "Partition", I see what is in the attached photo. "Apply" is grayed out, so I need to change something from these settings...

     

    Attached Files:

  8. kschendel macrumors 6502a

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    #8
    Yes, you select the physical disk. Maybe it wants you to give it a name other than Untitled? I dunno.
     
  9. clauditorium thread starter macrumors newbie

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    Aug 8, 2010
    #9
    Should I be concerned that it says the volume has 5.42 GB used space? Should I change the size option?

     
  10. Fishrrman macrumors G4

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    Feb 20, 2009
    #10
    You're going to have to get ahold of a USB flashdrive (with OS installer) that IS bootable.

    Once you have that, you're going to have to do the steps I outlined in post #5 above.

    Seems to me that -something- about the way the drive is currently initialized or partitioned is getting in the way -- which may be the source of your problems.

    The best way to "clean this up" is to "start fresh".

    Again, that means booting from an external source and starting over by reinitializing.
     
  11. clauditorium thread starter macrumors newbie

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    Aug 8, 2010
    #11
    I purchased a brand-new USB flash drive and turned it into an installer... and got the same results.

    One thing I haven't tried is using Target Disk Mode, but I'd have to buy a special cable to link the two computers, and at this point, I don't know if it's worth the expense.


     
  12. Bart Kela macrumors 6502a

    Bart Kela

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    #12
    In the end, it's your call how much time/money you want to spend on this endeavour.

    That's basically the point you've reached. For sure, no one here can tell you if you spend X dollars and/or Y hours that you will get a satisfactory conclusion.

    It's entirely your call right now how to proceed.
     
  13. clauditorium thread starter macrumors newbie

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    Aug 8, 2010
    #13
    Actually, scratch what I just said. I tried it again, and after a LONG time, the computer seems to have booted using the flash drive.

    My only question is, specifically what do you mean by "re-initialize the internal drive"? Do I select the Internal Physical Disk, or the Internal Physical Volume? And then do I choose "Erase" or "Restore" or "Partition"? If I choose Restore, what option do I choose next?

    Thanks in advance!



     
  14. Bart Kela macrumors 6502a

    Bart Kela

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    #14
    Personally, I would repartition the boot drive into two volumes, let that finish, then repartition that same drive into one bootable volume.

    To me, that would seem a sane step to recreating a healthy boot partition.
     
  15. clauditorium thread starter macrumors newbie

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    Aug 8, 2010
    #15
    I'm willing to try that, but can you explain what that would accomplish, specifically?


     
  16. Bart Kela, Jan 7, 2017
    Last edited: Jan 7, 2017

    Bart Kela macrumors 6502a

    Bart Kela

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    #16
    Well, it basically ensures that the system isn't running in some sort of weird damaged partition configuration.

    I keep a couple of external boot drives around, usually running previous versions of the operating system. Thus, I'd boot from one of those and reformat/repartition the internal boot drive with Disk Utility.

    That said, your initial description of your computer's problems make it sound like it might be more than a disk boot volume partition issue.

    I'm not a licensed Apple certified service center technician, nor do I have access to your system and the diagnostic tools that a such a person would use to diagnose your problems (just in the same way that oncologists don't offer diagnoses online since they can't perform MRIs, X-Rays or biopsies via anonymous Q&A forums).

    I recommend you have a professional with the right tools and experience to evaluate your device.

    Good luck.
     
  17. clauditorium thread starter macrumors newbie

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    Aug 8, 2010
    #17
    I just attempted to partition, and the operation failed.

    I was only planning to sell it for parts, so I don't think I'll be paying someone to look at it.

    I'm not sure if Fishrrman is going to answer me, so can you tell me what you think he means exactly by step #4 (see list below)? "Re-initialize" is not a term I understand. Does he mean erase? And if so, am I erasing the disk or the volume?

    1. Power all the way down to off.
    2. Reboot from the USB installer drive
    3. Once booted, go to Disk Utility
    4. NOW re-initialize the internal drive
    5. Before you quit DU, run the "repair disk" function on the internal drive.
    6. What kind of report do you get? Is it a good one?
    7. If you do get a good report, REPEAT the repair disk function FIVE TIMES in succession.
    8. Do you get a good report each and EVERY time?
    9. If so, NOW go to the Installer and try installing the OS once more.


     
  18. kschendel macrumors 6502a

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    Dec 9, 2014
    #18
    I'm pretty sure he meant "format, partition, install a filesystem." In Disk Utility I think that translates to using Partition at the physical disk level. I think what Bart Kela was after was making sure that you did something to change the on-disk formatting; so if it's one partition now, make it two, apply that, then make it one partition, apply that, and try to install onto the internal disk.
     
  19. clauditorium thread starter macrumors newbie

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    Aug 8, 2010
    #19
    I tried partitioning, and the operation fails every time. I don't know what's keeping it from working.

     
  20. kschendel macrumors 6502a

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    #20
    Does it explain why it failed? Maybe the disk drive has failed in some way.
     
  21. clauditorium thread starter macrumors newbie

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    Aug 8, 2010
    #21
    It says, "The volume could not be verified completely." and "Couldn't modify partition map because file system verification failed. Please verify and repair each volume individually and then" - it just cuts off at 'then'.

     
  22. kschendel macrumors 6502a

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    Dec 9, 2014
    #22
    I don't know why it's trying to verify partitioning or a filesystem, as the whole point is that there probably isn't one. Is this the installer doing this, or Disk Utility? If it's the installer, try running Disk Utility to erase and repartition the disk. If it's Disk Utility giving you that message, maybe try this:

    Open a terminal window, and type:
    diskutil list
    which should give you a list including the hard drive you're having problems with. Let's say it's /dev/disk1. Try:

    diskutil eraseDisk JHFS+ mydisk disk1

    Which in theory ought to erase the disk and reformat it with a single partition. Note that the last parameter is the disk number to reinitialize, make sure it's the right one because you don't get any "are you sure?" second chances! The "mydisk" parameter is the new volume name and you can make it whatever you want.

    If that works, try the installer to see if you can install to that disk now.
     
  23. clauditorium, Jan 9, 2017
    Last edited: Jan 9, 2017

    clauditorium thread starter macrumors newbie

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    Aug 8, 2010
    #23
    [EDITED]
    It's Disk Utility doing it.
    It says Disk0 is the "internal, physical" disk, and Disk1 is the "external, physical" disk. I pick the first one?
    (There's also a bunch of disk images.)


     
  24. kschendel macrumors 6502a

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  25. clauditorium thread starter macrumors newbie

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    Aug 8, 2010
    #25
    Just tried it. Result:
    Error: -69888: Couldn't unmount disk

     

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