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

did your mac mini come with SSD installed? if not then you may not have an Apple SSD ability

(attaching an SSD to some 3rd party sata thing that acts like an HD does not necessarily make it an SSD in Apple's view. all i know about that is for iMac 2015 the SSD support is built-in to the motherboard. i guess this depends on many things - how your motherboard and thus apple drivers "see things")

i'm running a mac min 2010 on high sierra have 0 prolems. i'm convince you people are hacking your boxes 🙂 for example: you didn't change the "partition scheme type" (guid or dos) on your startup disk did you? you didn't install (virus checkers, disk copiers, ugh disk encryption yuk, etc) software that hooks in to "extend Sierra ability" (which likely should be un-installed before attempting an OS upgrade incase any of those hooks activate)

unless a drive controller (ie sata board and any drivers to make that work) are broken you should be able to unmount unless the drive is in use. if you have (weird) software running that is using it, you can't unmount it? well you might see if umount -f (force unmount). but i'm guessing that's not the real issue.

there ARE problem reports on installing the NEW FILESYSTEM APFS on HD which is rumored to be corrected in the future. I'm only assuming you all saw that and did not select to try apfs though it was not automatically selected.

I have the same problem when trying to install High Sierra on a Mac mini with SSD (actually running Sierra). Installation stops with said Message:

MacOS could not be installed on your computer

Unable to unmount volume for repair

Quit the installer to restart your computer and try again.

I repeatedly tried, from internal drive, from external bootable disk, with new Installer. Always the same message as above. I also tried to unmount and do first aid with the SSD, also without success.

There are two things remaining:

1. Apple delivers a new Installer, fixing the above problem?

2. Reformat the SSD, installing High Sierra on the new formatted SSD disk and import a time machine backup.

Is there a change to be successful with Nr. 2?

Was there somebody already successful with Nr. 2 for the given problem?

Or, is there a chance that Apple will release a fixed new installer?

Thanks in advance!

•If any disks/partitions being backed-up are case-sensitive, the backup volume must be, too, so select Mac OS Extended (Case-sensitive, journaled). http://pondini.org/TM/5.html

Personally, I never use case-sensitive.

Rather than use Time Machine > Restore, if you are able to view the Backups.backupdb folder you can drill down to find your data and try dragging it over to your drive.

If you don't have a clone backup it's time to start. Just like a seat belt and an air bag protect you in different ways when driving, you need both Time Machine and a clone for full protection. Restoring from a clone or manually dragging over from a clone is easier IMHO than using Time Machine.

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)

I suspect the problem with with your version of MacMini. I see reports from MacMini users on other forums. Apple needs to do something to make this work on the older MacMini drives.

Apple doesn’t routinely monitor the discussions. These are mostly user to user discussions. Send Apple feedback:

BugReporter http://bugreporter.apple.com

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Mac OS X Feedback (no account needed)

https://www.apple.com/feedback/macos.html

So finally managed to get things going. My bad, I’m such a burn out, I was attempting to do all this in recovery mode, finally realized my error and went into internet recovery mode and then I was able to get things rolling. Ran first aid, said drive had errors, ended up just wiping the the whole drive and doing a restore from time machine. All good, restored perfectly everything working, however, upon reboot and it all loaded up and the high Sierra installer was still there cause it was downloaded when I backed up before attempting install. So I thought why not, I’ll try the commands everyone been using here in terminal but both commands say no such file or directory so as it stands now I don’t think high Sierra is not meant to be for me. Sierras been working fine all this time. Apple defiantly not on there game with this version of operating system.

You need to delete the previous installer from your applications folder.

Migration should work to bring back your data from Time Machine or you can erase then restore from CCC.

I have the exact same issue with a late 2016 27-inch iMac with 1TB SSD. I've tried disk utility repairs both in Sierra, while in the High Sierra installer, and by booting into recovery mode. I've also re-downloaded the installer several times. I had no issues upgrading on my older iMac, 15-inch Macbook pro with touchbar, or VMs.

Relevant snippet from the logs:

Sep 27 15:32:48 Hostname OSInstaller[560]: The volume 3AC2B122-F459-4D4D-9D57-6FD3735A61C8 appears to be OK

Sep 27 15:32:48 Hostname diskmanagementd[562]: diskmanagement: rawLaunch_block_invoke: waitpid(2) pid=586 ret/errno=586/35 status=0x00000000 exit=0

Sep 27 15:32:48 Hostname OSInstaller[560]: Storage system check exit code is 0.

Sep 27 15:32:48 Hostname OSInstaller[560]: Repairing file system.

Sep 27 15:32:48 Hostname diskmanagementd[562]: diskmanagement: [DMToolMountMisc _DAOperation_performsync_:disk:options:mountpoint:arguments:asEUID:asEGID:timeo utSec:dissenter:dissenterPID:]: [un]mount failed: err=-69888 un0mt1=0 timeout=0 dissenter=1 dissenterpid=0 dissenterstatus=49168=0xc010

Sep 27 15:32:48 Hostname OSInstaller[560]: Volume could not be unmounted.

Sep 27 15:32:48 Hostname OSInstaller[560]: Restoring the original state found as mounted.

Sep 27 15:32:48 Hostname OSInstaller[560]: Disk repair retry failed too many times. Will hard fail.

Sep 27 15:32:48 Hostname OSInstaller[560]: Clearing automation and attempting to rebless. source volume: SKCSDisk { CSLV UUID: F9058AC2-96C9-44DA-8889-926055B945FF CSLVG UUID: 3AC2B122-F459-4D4D-9D57-6FD3735A61C8 BSD Name: disk1 Mount point: /Volumes/Macintosh HD Role: kSKDiskRoleMacSystem Type: kSKDiskTypeCSLV } rebless: 8B9F5F16-6CFA-3E48-ACAA-4EF7ADC213B5

Sep 27 15:32:48 Hostname OSInstaller[560]: OSIInstallElement <OSIRepairDiskElement: 0x7f9e55ba1300> errored out:Error Domain=com.apple.DiskManagement Code=-69673 "Unable to unmount volume for repair." UserInfo={NSLocalizedDescription=Unable to unmount volume for repair.}

Sep 27 15:32:48 Hostname storagekitd[561]: storagekitd: copyDiskForPath returned nil, error: -69808

Sep 27 15:32:48 Hostname storagekitd[561]: storagekitd: copyDiskForPath returned nil, error: -69878

Sep 27 15:32:48 Hostname OSInstaller[560]: ------- Install Failed -------

Sep 27 15:32:48 Hostname OSInstaller[560]: Operation: Verify and repair disk failed, Failure Reason: Error Domain=com.apple.DiskManagement Code=-69673 "Unable to unmount volume for repair." UserInfo={NSLocalizedDescription=Unable to unmount volume for repair.}

I also have the same issue with a Late 2012 Mac Mini i7 Server that I have installed an Intel 540s 1TB SSD as the boot drive.

Something else to note is that when you quit the High Sierra install and restart to Sierra, TRIM is disabled on the SSD and needs to be re-enabled with "sudo trimforce enable" from terminal.

I have just tried the new release of the High Sierra installer 13.0.66 and still have the same issue.

I don't have a MacMini so haven't followed closely but it seems updating the MacMini to High Sierra has been problematic for users. I wonder if this could be a firmware issue.

Check for the Apple Feedback.app in System folder. Normally this app is only a part of the beta but some users have reported it's now an option for non-beta users.

Macintosh HD Root folders

Applications

Library

System/Library/CoreServices/Applications/Feedback Assistant.app

Users

Select Keep in Dock for easy access after launching.

You might consider enrolling in the Public beta. This way you can send detailed reports to Apple to help fix the issue.

Apple Beta Software Program

Hello,

Step 2 may apply if you have an encrypted hard drive.

Please try umount forcing again (repeat steps 4 to 6).

If this solution fails, you may try to repeat it exactly as I did it:

Install normally till you get the installation failed message.

If you left click click some empty spots at the window with the error, you'll get a Mac menu just like in recovery. You'll then be able to open the terminal and run steps from 4 to 6. I did try conversion once with the volume mounted. It failed. I force umounted. And then conversion worked flawlessly.

This error is very irritating, it took me 2 days to be able to boot my Mac again, nothing I found on the internet helped, so I hope this procedure works for you guys as well.

A clone is part of a good backup strategy. It's bootable where Time Machine is not. It's a bit easier to manually drag over files if needed. If you have a clone, you can select to import from the clone rather than select migration from Time Machine when setting up a new Identity. I mentioned so you can incorporate in the future for your backup strategy.

However being specific to upgrading to High Sierra....Since you have problems with restoring from Time Machine due to the case-sensitive issue, it appears you will need to manually do a clean install. Restoring to a server is also a different scenario and should have been mentioned for users to know what to suggest. I have no experience with setting up a server. It might be beneficial to start a new post with specifics to your issue and with full details. Users with the specific knowledge to help with setup of server will be best able to advise you.

No wipe. My procedure preserved all my data. It’s exactly the same conversion the installer does. The problem is that it does not force umount

I just notice Apple did update the installer again

frist time was on on 5 October

and now on 12 October

did anyone tried new version ?

I've tried everything short of booting off of a linux thumb drive and zeroing the hard drive on my 2012 Mac mini. I can't even get it to let me force an unmount of the hard drive in order to check the disk for errors.

For the record I'm booting off a USB installer I created for High Sierra