IMac – Problem installing High Sierra 10.13.4

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I have an iMac 27" Late 2015 with High Sierra installed. When I bought it, it came with Sierra installed, and when High Sierra was released I made a clean install but formatted my Fusion Drive to APFS. I had some problems but finally I got the 10.13.3 working properly. Now when I try to update to the 10.13.4 it simply doesn't update. Nor via Apple Store, not via downloading the whole installer of the update. And when I try to reinstall the whole system via a thumb drive I receive the “an error occurred while preparing the installation. Try running this application again” message. I have already corrected the date but even though it doesn't install. Any suggestions?

Best Answer

FWIW I had huge problems running 10.13.2 thru 10.13.4. I'm on an Apple RAID that's HFS+ formatted. But apparently Apple suddenly dropped support for all RAID, even their own. Very annoying. Fusion is not a raid but it's kind of raid-like in many ways, I can see how that could cause the same problem I've been dealing with. The update runs through the whole process, everything seems to work, then it reboots and is still on the old OS.

But here's how I finally had to upgrade my system: I had to clone my boot drive (the striped RAID) to a USB drive. Boot off that USB drive, and run all system software updates. They worked fine off a single, normal drive. Then I cloned back to my RAID volume. And obnoxious solution for sure, but it worked in my case, it may work for you.

Make sure you have a functional, up-to-date Time Machine backup

To do this I did a manual Time Machine backup than deleted and restored a file I care about.

Download High Sierra and make and an installation drive

Download the High Sierra installer from the App Store. Attach the USB thumb drive to your Mac and then make a bootable, High Sierra installation disk out of thumb drive by running the following in Terminal:

sudo /Applications/Install\ macOS\ High\ Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/Untitled --applicationpath /Applications/Install\ macOS\ High\ Sierra.app

Where /Volumes/Untitled should be replaced with the name of your USB thumb drive.

Format an external drive and install High Sierra on that drive

I used an older 500GB LaCie I keep kicking around for just these cases. It's fast and built well so I can trust it. Use the attached thumb drive to run the High Sierra installer. When asked which drive to install the operating system on to, click the Show More Devices button and select that USB hard drive. The installation should proceed without a problem and when the computer reboots you'll be booted from the remote drive and dropped into High Sierra. You can skip the first boot setup. You won't be using this for very long. Just make a temp account and get to logging in.

Force unmount the internal fusion drive and format it

Here is where the scary bit begins. You're going to force unmount the fusion drive because it'll still be mounted (and stuck) when you boot the external High Sierra image. To do this I opened up Terminal and ran:

sudo diskutil unmount force /Volumes/Macintosh\ HD

You should replace /Volumes/Macintosh\ HD with the name of your fusion drive before you run that command. Once the drive is unmounted you can format it like so:

sudo diskutil reformat /dev/disk2

You should replace /dev/disk2 in the above command with whatever your disk number is for your fusion drive.

Install High Sierra to your fusion drive using the installer

With the drive wiped you can proceed to install High Sierra on it using the USB thumb drive you turned into a bootable, High Sierra installation drive. Same as before, run the High Sierra installer from the thumb drive and when it asks you which disk to target select Show More Devices and find your fusion drive in the list.

The installation should proceed without a problem now and when your machine reboots you'll be booted from the internal drive.

Follow the first boot prompts and restore from your Time Machine backup

You'll have to pick your region, connect your keyboard and mouse, and then setup WiFi. Once that is done the first boot process will give you the option to restore the computer from a Time Machine backup. Select this option. Select everything on the backup that you want restored and follow the prompts.

Once the restore is complete you should have a functioning High Sierra installation with all your data and user accounts on it.

MacOS – How to include recent security patch (APFS plain password vulnerability) into already downloaded macOS High Sierra installer image

You can't merge an update into an older macOS installer app easily. So you have to re-download the full installer to get the most current version. Check that you don't get the restricted (20 MB) installer only app.

After downloading the first full installer (without installing it), move it to a folder and create a dmg choosing the folder (or alternatively zip the app).

Then install the upgrade or trash the macOS installer.app.

After Apple announces and publishes a new installer (not necessarily as a point release update), download it again. Repeat the steps above. If you don't need the old installer.dmg anymore, trash it. I usually keep them.

Under certain circumstances (often after moving the macOS installer.app to an arbitrary folder) downloading the new release will replace the old macOS installer in-place.

To check the build version grep the the file /Contents/Info.plist for DTSDKBuild:

grep DTSDKBuild -A1 .../Install\ macOS\ High\ Sierra.app/Contents/Info.plist

The golden master's build version was 17A362a.

The first installer's build version available to the public was 17A364.

The latest build version as of today is 17A400 (small installer) or 17A403 (large installer).