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My 2013 iMac crashed and I can't access it any form. Not Safe Mode or Recovery. I removed the drive and want to access some of the files. It's old and was slated for replacement later this year. Should I be able to mount the drive on a different Mac and see its file structure, assuming the disk is okay?

Update:

Output from diskutil list, after attaching HDD as an external drive to another Mac.

/dev/disk3 (external, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *1.0 TB     disk3
   1:                        EFI ⁨EFI⁩                     209.7 MB   disk3s1
   2:          Apple_CoreStorage ⁨Macintosh HD           ⁩ 999.3 GB   disk3s2
   3:                 Apple_Boot ⁨Recovery HD⁩             650.1 MB   disk3s3

diskutil cs list

CoreStorage logical volume groups (1 found)
|
+-- Logical Volume Group 879B94FC-E0C8-4DEB-838A-9F65078FFDA3
    =========================================================
    Name:         Macintosh HD
    Status:       Offline
    Size:         999345012736 B (999.3 GB)
    Free Space:   -none-
    |
    +-< Physical Volume 5CA40245-A547-42CE-A283-8A855191C7F5
    |   ----------------------------------------------------
    |   (No properties)
    |
    +-< Physical Volume FF551275-7077-4759-870E-2AA51B847383
        ----------------------------------------------------
        Index:    1
        Disk:     disk3s2
        Status:   Checking
        Size:     999345012736 B (999.3 GB)
11
  • Is the drive a HDD, SSD or both (Fusion drive)? What version of macOS is installed on the 2013 iMac and the other Mac? Commented May 8, 2021 at 21:09
  • 1
    I hope you manage to recover your files, but also that you appreciate why having a backup is essential.
    – benwiggy
    Commented May 8, 2021 at 21:28
  • Thanks for your help. It looks like the drive is toast. It doesn't mount on finder. It shows up in Disk Utility but as an unformatted drive and running first aid yields: Incomplete or inconsistent CoreStorage Physical Volume set Problems were found with the partition map which might prevent booting Storage system verify or repair failed. : (-69716) Commented May 8, 2021 at 21:33
  • 1
    Are you sure your Mac did not have a Fusion drive. If you did, then there might also be a SSD in the Mac. You would need both to recreate the Fusion drive. Commented May 8, 2021 at 22:39
  • Can you give, external disk connected, the result of command diskutil list?
    – user415185
    Commented May 8, 2021 at 22:47

4 Answers 4

1

You may be able to use a disk recovery utility like Disk Drill.

Recovery utilities scan the blocks on the disk and attempt to string the blocks together into whole files. I don't know how well they work with HDDs taking from a Fusion drive, but you have nothing to lose.

Downloading Disk Drill (and similar software) is free to install and scan your disk. But you will need to pay if you want to recover any of the files it finds.

3
  • @Jean_JD In 2 Parts:...CoreStorage logical volume groups (1 found) | +-- Logical Volume Group 879B94FC-E0C8-4DEB-838A-9F65078FFDA3 ========================================================= Name: Macintosh HD Status: Offline Size: 999345012736 B (999.3 GB) Free Space: -none- | +-< Physical Volume 5CA40245-A547-42CE-A283-8A855191C7F5 | ---------------------------------------------------- | (No properties) Commented May 10, 2021 at 4:11
  • | +-< Physical Volume FF551275-7077-4759-870E-2AA51B847383 ---------------------------------------------------- Index: 1 Disk: disk3s2 Status: Checking Size: 999345012736 B (999.3 GB) Commented May 10, 2021 at 4:11
  • @Peter Can you update your question with this informations in "code" mode?
    – user415185
    Commented May 10, 2021 at 7:15
1

Yes you can, as long as you put the disc in a usb 3 enclosure, compatible with your new Mac.

Edit after result of diskutil cs list.

Your HDD is part of a Fusion Drive :

HDD present :

+-< Physical Volume FF551275-7077-4759-870E-2AA51B847383 
                ---------------------------------------------------- 
                    Index: 1 
                    Disk: disk3s2 
                    Status: Checking 
                    Size: 999345012736 B (999.3 GB) –

SSD absent :

+-< Physical Volume 5CA40245-A547-42CE-A283-8A855191C7F5 
                | ---------------------------------------------------- 
                | (No properties) –
1
  • I think we know that the disk is in an enclosure and is connected to the new Mac. The problem is that it can't be mounted. But let's wait and see the updated question with the output of diskutil cs list.
    – Gilby
    Commented May 10, 2021 at 11:33
1

Sorry not to have answered earlier, but only now I saw the question.

First off - you didn't have to extract the hard-drive from the old Mac to access it. Every Mac I know has a "Target Disk Mode" meaning, you boot the Mac while holding the "T" on the keyboard, and the Mac becomes.... an external hard drive! you can then connect it to any other Mac and access it.

Next, since you do experience problems with this hard drive (can't boot) there's good chance it is malfunctioning at some level - maybe just a few bad sectors, maybe it's on the verge of dying, maybe already dead. In any case - it is not wise to use any disk-fixing utility or actually any program that may attempt to change anything on the drive.

There are two things I would do:

  1. First, find some good S.M.A.R.T status utility that can query the drive and provide detailed information about its hardware state (e.g. Volitans https://www.volitans-software.com/apps/smart-utility/)
  2. Find a good non-destructive disk recovery program (I'm addicted to the old "DiskWarrior" from https://www.alsoft.com) which reconstructs a drive all in RAM, mounts it for you on your desktop so you can play with the pseudo hard-drive and copy whatever you can to a good backup drive, and only then - it can attempt to fix the original.

Good luck!

1

I'm going to go out on a limb and try to answer the question that you may be thinking but not asking directly: Is there any way to recover my non-functional hard drive and/or computer?

A: Yes, you are in luck there are several options.

  1. First, if your computer is completely failing to start, even in (normal) Recovery Mode, it's very likely that you have an NVRAM issue and fortunately this is super easy to fix by resetting the NVRAM. Here are the steps from Apple's official support docs:

Shut down your Mac, then turn it on and immediately press and hold these four keys together: Option, Command, P, and R. You can release the keys after about 20 seconds, during which your Mac might appear to restart.

  • On Mac computers that play a startup sound, you can release the keys after the second startup sound.
  • On Mac computers that have the Apple T2 Security Chip, you can release the keys after the Apple logo appears and disappears for the second time.

Please visit this support page for more details: https://support.apple.com/en-us/HT204063

  1. If reseting the NVRAM didn't help, and you are not able to use the normal Recovery Mode (as you mentioned in your question), you have another option: Mac computers have something called Internet Recovery Mode. This mode downloads a recovery OS from the internet and allows you to run basic operations on your computer. After booting into Internet Recovery Mode, you can use the native macOS/OSX Disk Utility app to try to correct whatever software issues your disk may have.

To manually start up from Internet Recovery, press and hold either of these key combinations at startup:

  • Option-Command-R
  • Shift-Option-Command-R

Please visit this support page for more details: https://support.apple.com/en-us/HT201314

  1. If running Disk Utility in Internet Recovery Mode doesn't solve your issue, then as @Motti Shneor suggested, you can try connecting your mack to another computer using Target Disk mode and copying over your files.

Connect the two computers with a FireWire or Thunderbolt cable. On the Mac you want to use as the disk in target disk mode, do one of the following:

  • If the computer is off, start it up while pressing and holding the T key.
  • ...

Please visit this support page for more details: https://support.apple.com/guide/mac-help/transfer-files-mac-computers-target-disk-mode-mchlp1443/mac

  1. If Target Disk Mode doesn't work, but you have the option of either using Internet Recovery Mode (or pulling out your hard drive and plugging it in to another computer), there are some great command line tools for recovering data from a corrupted hard drive. Please see my previous answers here and here for details. I've personally used both of these, and they are good for the following use cases:
  • The first option is a native dd command. This will attempt to copy your entire disk into a mountable disk image file on an external drive. While doing this, it will replace any physically damaged sectors of the hard drive with zeros: This means all of your undamaged data will be fully accessible without any issues on the new disk image.
  • The second option is to use PhotoRec (a third party command line tool), which will attempt to bruit-force read all the data from your hard drive and look for specific file types in it. (You can specify the file types you want when you run it.) This is useful in case your boot sector somehow got destroyed leaving your hard drive inaccessible. (Please note though, both of these options require your hard drive to be un-encrypted, and for you to have at least some degree of read capability on it.)
  1. Continuing from #4: If your issue really is due to a damaged boot sector, you may not need to spend the many hours it will take to run PhotoRec. Check out this almost-magic guide to try to fix your damaged boot sector using TestDisk (another third party command line tool). (Again this requires your hard drive to not be encrypted and be at least somewhat accessible.)

  2. Lastly, if you reached this far, it's probably because your hard drive was encrypted and you're about to give up hope. Fear not, you still have 2 more options! First, when you encrypted your drive, Apple would have given you a prompt asking if you wanted them to save your encryption key on their server. If you agreed to do this, you might be able to reach out to Apple Support and ask them for help to decrypt your hard drive. Second, if you didn't trust Apple with your encryption key, fear not! It's actually not that hard to decrypt a hard drive. While I haven't done this myself, I knew someone who had, and apparently it's not that hard to find tutorials on it. (As a personal example, a couple years ago I stumbled on an official tutorial from Intel about how to decrypt a hard drive using one of their tools. So there are articles out there if you've got the patience to find them.)

Closing remarks:

In the first few options above, I gave some keyboard shortcuts to use while trying to boot your computer. You can find a summary of these (and other useful commands) on this Apple support page: https://support.apple.com/en-us/HT201255. Quickly glancing over this page, I see a few more options that might be able to help you fix your computer, but I didn't list them in my answer because I have not personally tried them, so feel free to try them out if nothing else helps.

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