High Sierra install fails - "unable to unmount volume for repair"

Building upon previous answers, I have concluded that the problem is because the installer is glitched and can't convert the drive to APFS. This problem can easily be circumvented:

1 . Boot to internet recovery or a USB drive with the High Sierra Installer (standard Sierra recovery mode won't do).

2 . Go to Disk Utility and mount your Mac volume.

3 . Close Disk Utility and go to the command line terminal.

4 . Do diskutil umount force /Volumes/Macintosh HD/

Take note of your disk id. disk1 in my case.

5. Run diskutil apfs convert /dev/disk1s1

(replace disk1 with your disk id if needed)

6. Once this is done, reboot and High Sierra can be installed from either a USB drive or Internet Recovery mode (option+command+R)

Contacted AppleCare. These two commands fixed the problem: sudo mv /.quota.ops.user /.quota.ops.user.org and mv /.quota.user /.quota.user.orig

I had "success" by doing the following:

1. Boot into internet recovery mode Option-Command-R

2. Open Terminal and force unmount the drive

•diskutil list

•diskutil unmountDisk force /dev/disk<number>

3. Open Diskutil and reformat the drive to APFS ****Note that you will lose any data stored on the drive****

4. Install High Sierra

I tried disabling time machine, running disk recovery, re-installing Sierra through recovery mode (failed / file unavailable), re-installing High Sierra via recovery mode (installer failed), installing Sierra via a USB drive (hold down option, select USB drive with image on it), and probably something else I'm forgetting to mention.

I had intended on further testing/troubleshooting how to get this to work without blowing away my install but my TimeMachine backup (took 12+ hours to restore) somehow prompted me for the wrong Apple ID (I had changed mine about a year ago) and wouldn't let me progress with the restore past that.

Given the time I've spent trying to fix this it is ultimately faster to just flatten and re-install.

Boot into the Recovery Drive to run First Aid from Disk Utility in Recovery.

Boot into the Recovery Drive by holding down Command R when restarting.

Open Disk Utility

Run First Aid on your internal drive, Macintosh HD

Quit Disk Utility

Also check to be sure the firmware is fully updated on your Mini.

About EFI and SMC firmware updates for Intel-based Mac computers - Apple Support

https://support.apple.com/en-us/HT201518

Turn off Time Machine in System Preferences.

Remove all external devices.

Restart in safe boot mode.

Try running the installer now.

Follow these steps to start up into safe mode.

1. Start or restart your Mac.

2. Immediately after you hear the startup sound, press and hold the Shift key.

3. Release the Shift key when you see the Apple logo appear on the screen.

I finally succeeded, very painfully! Here is what I have to share:

There was absolutely no way to unmount my ssd (not with external bootable drive, not with disk utility, not over the recovery system, nothing, ...) except when I ran the mac mini with the ssd in target mode. There I could use the Terminal and do a diskutility unmountDisk force /diskXXX.

The rest was some work with installing and restoring from time machine backup. Now everything is fine.

But I think there is a problem with unmounting some ssd in OS X, I dont know whether it is a problem with OS X or with the ssd?

While in Recovery Drive....

Open Terminal....

Check for the exact name of the disk:

sudo diskutil list

(you will see the list of drives/partitions, take note of which one is the one you are trying to unmount/format, should be something like /dev/disk<number>)

Then to force unmount disk:

sudo diskutil unmountDisk force /dev/disk<number>

You should get a response to the success or failure to the unmount command.

If drives fails to unmount...

Check for an fsck process:

ps -ax | grep fsck

and then killed that process:

sudo kill <process number>

When drive is unmounted, force format the disk:

sudo diskutil erasedisk JHFS+ Untitled /dev/disk<number>

Once you have an empty disk formatted a HFS+ Mac OS Extended Journaled, you can select to install High Sierra and it will convert it to APFS

First off, congrats on your first Mac! I'm sorry you're having a bad experience so far with the install process (for what it's worth, High Sierra was the first in install issue I've ever personally had with Macs, they're usually very good with this sort of thing). Here's what you need to do for the install to work:

1. Boot up your Mac normally as if it were any other day
2. Press the "Command ⌘ + Spacebar" keys at the same time to bring up Spotlight. Spotlight looks like a thin, long window where you can do nothing but type, the idea being that at any time no matter where you are or what you're doing on your Mac, you can press these keys, type something, and it will search your entire Mac. Pretty neat!
3. In the Spotlight window, type "Terminal" and press the "return" key
4. You'll see a plain, white window pop up. This window is where you'll enter the commands everyone's been talking about. The program you've just opened is called "Terminal" and is used by developers and "pro-sumers" to do advanced computer tasks using text instead of dragging-and-dropping / clicking things like we normally do with a mouse.
5. In the Terminal window, copy paste this command exactly and press the "return" key:

   sudo mv /.quota.ops.user /.quota.ops.user.org

6. We're going to do the same thing again, only this time with a different command. Remember to press the "return" key after pasting it in:

   mv /.quota.user /.quota.user.orig

7. That's it! You can close the Terminal window and go about the macOS High Sierra install normally, as if you never did any of this at all. Assuming nothing's changed since when I did this, the install should work this time.

Please let me know on this thread if you run into any other issues, I'm happy to help 🙂

Thanks for waiting! To execute the commands from the Recovery Partition, here's what you do:

1. Boot into the Recovery Partition and click the "Utilities > Terminal" menu item to launch Terminal
2. In the Terminal window, copy paste this command and press the "return" key:

   ls /Volumes/

3. A list of partitions will be displayed, one of which is your primary macOS one. By default, it's named "Macintosh HD", but it's possible you renamed it at some point. Note the name if you did rename it and substitute it for "Macintosh \HD" at the points noted below. Otherwise, you can just copy paste the commands as they are! 🙂
4. In the Terminal window, copy paste this command (changing "Macintosh\ HD" if necessary") and press the "return" key. NOTE: If you changed the name at some point earlier and it has spaces in it, you'll need to put '\' before spaces for the command to work. You can try pressing Tab to help you autofill the name, if needed.

   ls /Volumes/Macintosh\ HD/

5. If this command executes successfully you should see "Applications", "Library", "Users", etc. printed. That's good news! That means you've selected the right partition, you're almost there. If not, you may have selected the wrong one, go back to 2. and try another one.
6. In the Terminal window, copy paste this command (again, changing "Macintosh\ HD" to your personally named partition, if necessary), and press the "return" key:

   mv /Volumes/Macintosh\ HD/.quota.ops.user /Volumes/Macintosh\ HD/.quota.ops.user.org

7. And finally, paste this in followed by the "return" key (again, changing "Macintosh\ HD" if necessary):

   mv /Volumes/Macintosh\ HD/.quota.user /Volumes/Macintosh\ HD/.quota.user.orig

As mentioned before, if your machine's not booting normally I doubt this will help, and if it doesn't work you'll have to reinstall macOS Sierra from the Recovery Partition or from Internet Recovery (this will NOT overwrite your personal data, it will only write over system-level files). Once you can boot normally again you try again by following these steps exactly.

Your best option might be to revert to the original OS X that came on your Mac using Internet Recovery. Then you can update to Sierra or High Sierra.

• Internet Recover will re-install the version of OS X that originally came with the Mac.
• Requires macOS Sierra 10.12.4 or later Reinstall the macOS that came with your Mac, or the version closest to it that is still available.

Shut down.

Immediately after hearing the Mac boot chime, hold dhown Shift Opt Cmd R. Keep holding until you see the progress bar. This will boot you into Internet Recovery.

Open Disk Utility. Select Macintosh HD and select Erase. Make sure you have formatted as HFS+

Quit Disk Utility.

Select to reinstall OSX.

Do not select to import any data after installing. You will want to upgrade before bring over any data.

Just to be clear, while in Recovery Drive > Disk Utility, you can't unmount the internal Macintosh HD to erase the drive.

In Recovery > Disk Utility, unmount all external drives.

In the Terminal type

diskutil list

This will get a list of your drive.

The output will look something like this:

Dianes-iMac:~ diane$ diskutil list

/dev/disk0 (internal, physical):

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *121.3 GB disk0

1: EFI EFI 209.7 MB disk0s1

2: Apple_APFS Container disk2 121.1 GB disk0s2

Using the info for your drive, use this command to unmount.

diskutil unmount /dev/disk0

If the drive still fails to unmount, it's possible that the drive is failing. Often Spotlight cannot let go of a failing drive. Not sure if disabling Spotlight while in Recovery will help, but it's worth a shot.

sudo mdutil -a -i off

If this fails, I would attach an external drive that is formatted as GUID. Select to install macOS to the external drive. You will boot from the external drive in a new High Sierra install. It will be formatted as HFS+ since it's a rotational external drive. While you are booted from the external you can try erasing the Internal drive. You might find this will give you more options than while booted from recovery.

First Aid from a booted drive cannot fix all problems. You must be booted from an external drive in order to fully repair a drive.

Something is running on that drive that is not allowing you to unmount. First disconnect any external drives then try booting into Recovery Drive and see if you can run First Aid now.

If you still have problems, how comfortable are you using the Terminal? See this link for help unmounting.

http://osxdaily.com/2013/05/13/mount-unmount-drives-from-the-command-line-in-mac -os-x/

Try umounting it again. Since I waited till installation was complete before posting, I forgot I got this error the first time, but umounting and retrying conversion worked for me.

In my case I had to mount because my drive was encrypted, so it couldn’t be automatically mounted.

If deleting the installer in Applications > Install macOS High Sierra fails to allow you to download, use Recovery Drive - use second option below:

Recovery Drive Options:

• command R to reinstall the latest macOS that was installed on your Mac, without upgrading to a later version

• option command R to upgrade to the latest macOS that is compatible with your Mac

• shift option command R to reinstall the macOS that came with your Mac, or the version closest to it that is still available

Since you are having so much trouble, instead of downloading and installing on top of your current data, I would advise you clone your drive first. Boot from the clone and erase your internal drive. Run the High Sierra installer and select destination drive as your internal drive, Macintosh HD.

After booting into High Sierra, you can manually bring over your data or use migration. I wouldn't use migration if you haven't done a clean install for a while.

Software used to Clone:

CarbonCopyCloner http://www.bombich.com/download.html (All options are available free for 30 days)

SuperDuper! http://www.shirt-pocket.com/ (Free forever to do an erase and install. Purchased version allows for smart updates and schedules)

Power down machine and boot into single user mode, it will have a black screen and white text, this is loading all systems support files + drivers, once all is processed, type. fsck -f (File System Check -Force), once done reboot and try again...see if all is well. ping back once you are able to.