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Mojave install not working

I ran the Mojave install and after the installation ran for about 15 minutes it restarted and eventually finished with the following message;


macos could not be installed on your computer


The operation couldn't be completed. (com.apple.DiskManagement error -69854.)

Quit the installer to restart your computer and try again.


I contacted Apple support who told me to power off the computer then power back up with Command R being held together until the Apple logo appeared then let go. This brings up a utility type window with the option to install the macOS. I did this several times but still got the same error. Has anyone else experienced this and if so were you able to fix it?

Posted on Sep 25, 2018 6:27 PM

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Posted on Sep 30, 2018 6:49 PM

After trying starting from the macOSX utilities window (command-R at start up), I was able to restore from the latest time machine backup. I tried several times to install Mojave but keep receiving the 69854 error message. Apple support suggested I wait for the 10.14.1 update to come out. I suspect this is a fusion drive issue but have no way of knowing for sure. I was just glad to have had a a Time Machine backup prior to trying to install. This is the first time I've had to use it and highly recommend everyone do this before attempting to install. Apple support worked with me the entire weekend and were very supportive and apologetic for not being able to finish the installation.

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Sep 30, 2018 6:49 PM in response to largewoodenbadger

After trying starting from the macOSX utilities window (command-R at start up), I was able to restore from the latest time machine backup. I tried several times to install Mojave but keep receiving the 69854 error message. Apple support suggested I wait for the 10.14.1 update to come out. I suspect this is a fusion drive issue but have no way of knowing for sure. I was just glad to have had a a Time Machine backup prior to trying to install. This is the first time I've had to use it and highly recommend everyone do this before attempting to install. Apple support worked with me the entire weekend and were very supportive and apologetic for not being able to finish the installation.

Oct 1, 2018 1:52 AM in response to coop Mac

I have the same problem on my iMAC (late 2014) with a Fusion drive (journaled encrypted).

I had to boot from a backup image and restore High Sierra

Official Apple support (Belgium) told me that the problem had been reported by several users and that Apple was looking for a solution. As a result, they advised me to stick to High Sierra for the time being and to wait for a new update of Mojave.

Oct 4, 2018 5:52 AM in response to halcyonyarntech

Update: AppleCare replaced the fusion drive, returned my machine with High Sierra. I then asked them if I could upgrade to Mojave, and, they thought I could. I did. It seems to be working well.


So, I don't know if it is a different fusion drive model, and that's why it worked this time, or, if it was just an unfortunate coincidence that the original fusion drive was irreparably corrupted/broken during upgrading...


but that's the update!

Oct 18, 2018 3:36 AM in response to deberlin

For anyone else having this issue like I was/am: you don't need to restore from Time Machine if you happen to have a High Sierra USB hanging around (which I luckily did) or have access to another Mac you can make one with. See https://www.macworld.com/article/3204672/macs/how-to-create-a-bootable-macos-hig h-sierra-installer-drive.html for instructions on how to make one.


Just stick in the USB to the boot-looping machine, hold alt/option when it turning on, choose the USB High Sierra installer and then follow instructions to install High Sierra normally, and wait. Was back up and running within about 30mins.

Mojave install not working

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