Oct 04, 2017 Then I downloaded High Sierra from the app store. When it came up I quit the installer and then shut down the mac. Then restart the mac and immediately hold down the shift key to boot into safe boot keep holding down the shift key and let go when progress bar is near the end.
This morning I updated macOS High Sierra from 10.13.3 to 10.13.4. It appeared to install fine (I got to the login window), so I clicked on 'Shutdown', and when I got to the office, and turned on my Mac, it rebooted into recovery, with the Installer Log open, and a dialog that read, 'The macOS Installation couldn't be completed'. I called Apple and they had me run a check disk, and the boot-up volume didn't have any error. My internal SSD showed up just fine, to this poor chap. Apple also had me try to restart in Safe Mode, but the Apple icon got stuck at 100% progress (3+ minutes waiting).
So, since my drive appears to be intact (I used Terminal to browse my data), is it possible to undo the update or reinstall macOS High Sierra and have the system work as it was before the update (apps and data still accessible)? Note, I use Time Machine backups, and I have a 2TB drive with about 40% free space. There are lots of 'snapshots' on the volume. Is there a way to recover the system to the Time Machine snapshot? Or, will I need to reinstall macOS High Sierra? Since posting this, Apple called me back and they said that I should be able to reinstall macOS Sierra without formatting the drive and I should be back to the state I was before the failure.
I haven't tried this yet as I wanted to see if others have followed this or another procedure to recover from this failure without blowing up the hard drive and starting from scratch. In the past I have used a procedure for upgrading macOS versions that I had good successes with, especially when discussion groups and news are seeing problematic installs: using a system cleaner.
EG using something like Onyx before installing, then a reboot and proceed with the install. Yah, too late now for you but something to consider for the next time. If the restarting in Safe mode doesn't do the trick (it may.) If I were you I would use Recovery Mode and restore from a Time Machine backup. If I remember correctly you have the ability to restore from a specific point in time. Same problem; installation of 10.13.4 failed with 'could not be completed'.
I booted into recovery mode, ran disk utility repair and tried again after restoring from backup. Still no joy, and disk utility is now reporting lots of 'invalid internalflags'. Finally I restored again and I'm sticking with 10.13.3. Checking the fsroot tree. Warning: inodeval: object (oid 0x5edb): invalid internalflags (0x48000) warning: inodeval: object (oid 0x5edb): invalid pad2 (0x2a). Warning: inodeval: object (oid 0x5ee1): invalid internalflags (0x48000) warning: inodeval: object (oid 0x5ee1): invalid pad2 (0x2a) Checking the snapshot metadata tree.
Checking the extent ref tree. Checking the snapshots. Checking snapshot 1 of 3. Checking snapshot 2 of 3. Checking snapshot 3 of 3.
Verifying allocated space. The volume /dev/rdisk1s1 appears to be OK. File system check exit code is 0. Restoring the original state found as mounted. Operation successful. I got exactly the same problem: after 8-9 minutes got the message to restart because the update didn't work.
I had the same with the previous update, but didn't learn my lesson. Then I downloaded the update and with the dmg file managed to update. Mistakenly I didn't this time. So, first I restarted in safe mode, which worked, but when I restarted again back in normal mode, I got the same problem. Then I restarted with the space bar. Same problem. Then I restarted in recovery mode, and that finally worked.
However, regretfully my most recent time machine backup was 2 weeks old (I was traveling), meaning I lost 14 days of work. For the past hour I have been trying to download the dmg file instead of using the update via apple store. First attempt, the download got stuck at 577KB; second attempt stuck at 4.1MB. So, now I decided to wait & see and ignore the apple store message to update, until I read some good news.