Catalina installation error

How to fix a split Fusion Drive

If your Fusion Drive appears as two drives instead of one in the Finder, it's no longer working as a Fusion Drive. Here's how to fix it.

https://support.apple.com/en-gb/HT207584

If you're using macOS Mojave or later

1. Turn on your Mac, then immediately press and hold Command-R to start up from macOS Recovery. Release the keys when you see the Apple logo or spinning globe.
2. When you see the macOS Utilities window, choose Utilities > Terminal from the menu bar.
3. Type  diskutil resetFusion in the Terminal window, then press Return.
4. Type Yes (with a capital Y) when prompted, then press Return.
5. When Terminal indicates that the operation was successful, quit Terminal to return to the macOS Utilities window.
6. Choose Reinstall macOS, then follow the onscreen instructions to reinstall the Mac operating system. Your Mac restarts from your Fusion Drive when done.

I wonder if you have checked the ‘all devices’ item in the drop down at the top left of disk utility. When I tried to repair ‘container disk 2x’ which contained my Macintosh HD partition, I found it failed verification. As it turns out, there are a number of partitions that are not mounted which appear to have been created by the j stall routine (since Catalina creates two separate partitions, one for the Os files and one for data.

anyway, long story short... needed to recreate the fusion drive from the recovery terminal (after Backup, of course). After recreation, installation worked fine. Just restoring from tome machine now....

This approach worked for me after multiple passes with the other ones didn't, on a 2019 iMac..

The "needed to recreate the fusion drive from the recovery terminal" hint made me Google that, finding the matching Apple article:

https://support.apple.com/en-us/HT207584

I rebooted in "remote-rebuild" mode with the OPTION-COMMAND-R combination, this allowed my iMac to download the Catalina installer directly from Apple, then used the Terminal menu and issue the command:

diskutil resetFusion

This step was able to resolve all the issues with my Fusion drive (obviously by also removing all its content as it is re-created from scratch).

Exiting the Terminal, and using the re-install OS option allowed Catalina to finally install smoothly.

Fusion drives can be tricky to handle even for the OS itself..

Same error here! iMac Retina 5K 27-inch, Late 2015.

Ran Disk First Aid and received an error and tried to repair – no luck. Started up in Recovery mode and ran Disk Utility again with same result. The Fusion drive seems to have issues with no immediate user-friendly way to repair it.

HugoRod1024:

Suggestion #1 was a waste of half an hour. I did the Option + Command + P + R three times and then tried the Catalina install again. Same error as before.

This is definitely a Fusion hardware issue. I think that the drive is bad and needs to be replaced, so I'm taking my machine in next week.

Reformatting the Fusion drive and then restoring from Time Machine may get the job done, but there has to be a reason as to why the Fusion drive is getting messed up.

Great question, now you have a few tools to help you, but it is somewhat a technical verification; but easy enough for most if you go slowly!

First, this specific error (during MacOS install) is most usually in relation to the "quality" of you MacOS partition. Simply, your Mac paritition has errors and sometimes it may be recoverable... Let's check this now.

1 - Boot your Mac in Recovery Mode (hold together on your keyboard -> command + R).

2 - Once loaded -> give it a moment or so, go into Disk Utility app -> you should see a menu with 4 options including reinstall your OS, get help, etc.

3 - Once in the App, you will see the drives you have on your Mac. Make sure you select the drive that holds your main paritition (usually on the top left menu). That's usually where you want to install you OS. Now in the sidebar, select the volume you wish to repair.

4 - Click the First Aid button -> Click Repair Disk.

Now if nothing seems to work (and you still get errors), you may have to recovery a broken partition using Internet Recovery or a Time Machine backup. Now that's another subject!

Respect.

Here's a great web site for futur reference : https://www.idownloadblog.com/2016/02/26/how-to-use-disk-utility-in-mac-recovery-mode/

Unfortunately for my case, this did not help :( Both times the repair is successful (even in Recovery Mode) but I still get the error when installing Catalina. I get no errors during the disk repairs... very odd :(

I'm having exactly the same problem with the same model iMac. Mine has 3 TB fusion boot drive formatted to AFS. It is passing all the test in the disk utility program.

I have booted to recovery, run the re-install of Mojave, tried booting to USB but I cannot get an upgrade to run.

I'm reluctant to format the drive and do a new installation, It has taken my long enough to get the machine as I want it to start again!

Unfortunately I've had the same issue.

After trying the First Aid within the Disk Utility, it said there was still an issue on the HD (I too have a fusion). I eventually pulled all the files from my computer and did a clean install. It went back to Mojave 10.14. and while still being clean of third party apps or whatever I updated to Catalina. No more error.

It takes a little longer than you're used to, but it seems to work fine now. It might be the unconventional way to work because of the files and stuff. But it's also a great reason to clean up your computer ;)..

What's crazy is that I attempted this. I formatted the harddrive, installed a fresh new Mojave and when I attempted the update I got the SAME error. Very frustrating since it took a long while. I hope a solution can be found soon.

Same issue. Did the Disk Utility which reported no errors. Booted into Safe Mode, downloaded fresh installer - still got the same issue.

Really don't want to have to clean my Mac and start again but it's looking like I might have to... hopefully Apple comes up with an answer first!

iMac 5K Late 2014

Same here. Mac mini (Late 2012). From what I read in this thread, I figure this may be related to the use of fusion drive?

Checked APFS FS in recovery mode - no errors

Removed connected drives in case it was referring to an attached USB drive

Removed 32bit software.

Same message relating to "Storage system verify or repair failed".

Will raise a bug, since this discussion forum probably isn't going to get this fixed :)

JAA

Same exact issue on a iMac Retina 5K, 27inch, 2019 model. I already tried the recovery mode, disk util and tried 3 times installing and it starts off and then 45 minutes later, get that exact error code of -69716. Funny thing, I have an identical iMac at home and it installed without the error message.

Same issue - 69716 on an iMac (late 2012) with a 1TB Fusion Drive. Rebooted in Recovery Mode, ran Disk Utility and had no errors (finished 0). Tried to install Catalina again and got the same error. Reinstalled OS10.14.6 with no issues. Tried to install Catalina one more time and got the same error.

This is crucial and bad UX design by Apple.

All devices must be displayed so that the container can be selected and erased (formatted). Only by erasing the container will Disk Utility setup the extra volumes needed by Catalina. If you just erase the Macintosh HD volume (which by default is all that is shown) then only that volume is erased which means the Catalina install will fail because it cannot find the other volumes it needs (system and boot I believe).

Many thanks JA-A.