MDS Fails- Error: system reboot failed

I have been testing out MDS for possible use in our environment for the small number of Macs we have. I have created a Workflow that includes Mojave with about 8 applications. When trying to apply to either of my test systems It gets to 100% Preparing and then hangs showing the error that the system reboot failed. A manual reboot does not get the process to pick back up. Any help would be appreciated.
MDS v 1.6

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Are you installing macOS? It is macOS installer that does the reboot, so something in the hardware is stopping it. Try resetting the SMC and resetting the PRAM.


Hello Tim

I am getting this error on a 2015 iMac. I tried resetting the SMC and PRAM but no luck. I should note that I am trying a newer 10.14.5 OS.

Any guidance on this would be quite helpful.


after it fails, can you try opening a new terminal window and running “reboot” and see if it gives any error messages?



I did it today, and it just rebooted with folder and question mark. I guess fusion drives are a no go?


Huh. That is good info. We have an iMac with a fusion drive. We do testing on it and have not seen the issue. Is there anything special about your setup?

Just to add to this (New MDS v1.8 user here). I’ve now run into this while cleaning up some old inventory, specifically multiple MacBook Airs running El Capitan (10.11.6).

  • resetting PRAM doesn’t help
  • Doing a wipe + full restore of El Capitan/10.11.6 doesn’t fix it either [Along with doing all OS updates]
  • Opening new terminal window and issuing a reboot: machine reboots, but doesn’t start the installer (ie: returns to recovery mode).

Building a boot USB with High Sierra (didn’t try Mojave yet) and wipe/restore with that - does allow it to work in the future (ie: update to Mojave).

Hope that helps.

I’m currently using the pre-beta (pb) 1.9 and have not seen any issues. I haven’t run 1.6 in a while and definitely haven’t tried my workflow in that version. I updated through 1.7, 1.8 beta & pre-beta to the 1.9 pb before testing my workflow.

I’m sure there are some bugs in 1.9 pb, but I don’t thing I’ve stepped on them.

I’d give a newer release a try to see if that resolves any of your issues.


Jon: The error is generated near the beginning while Imagr has just finished preparing/loading the installer, and is (attempting to) rebooting into it.

I did see an error in the commands when Imagr attempted to format the disk (before loading the installer) - note this is different from Automaton formatting sequence. I don’t have the exact error, but next time I reset other MBA (got a few to go) I’ll copy it down. Probably had something to do with HFS/APFS mode detection.

Okay, while going through the pile of Air’s that need to be reimaged/updated (oh thank you MDS) here’s the error message in the beginning:

Imagr[xx:yyy] /usr/sbin/diskutil apfs list -plist failed with return code 1

From what I can surmise, the recovery partition (running v10.11.[4-6]) is incompatible with Imagr included with v1.8 of MDS.

Creating a boot usb with Mojave (to lazy to check Sierra/HS) and booting recovery off that (and then using the MDS image on that usb) does work fine.

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I am aware of the issue and working on a fix. thanks for reporting it.


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Awesome! MDS/Automon has saved me hours, so glad to help.

Side note for anyone else that popped up when I was playing around with these older (10.11) boxes. If you boot a 10.14 (mojave) usb, and use disk utils to format the disk as AFPS and then go do the image, you run into a situation that the computer firmware is unable to read the disk after that (good ol’ question mark folder). Solution is (obv.) to reformat back as HFS+/journaled, then reinstall. Mojave will do the firmware update and conversion on boot.

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Hi, I’m seeing this issue with a late 2015 iMac with Fusion drive installing Mojave. Any workarounds or fixes available yet? Thanks

An additional note. The original OS was El Capitan when it failed. I rebuilt the iMac using a bootable Mojave disk. I’ve run the process again and it’s worked this time.

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Hello, I recently have a lab of this kind of iMacs ( iMac (Retina 4K, 21.5-inch, Late 2015 - all on Sierra ) to upgrade - hopefully to Catalina or Mojave. We seem stuck on the same issue as above discussed. I tried to use Catalina, Mojave or even HighSierra as the installer for MDS but all failed with a typical msg: "Startosinstall failed with return code 10, Please look at the terminal output or check /var/log/install.log for more details ". They have internal Fusion Drive - all in good shape shows as one volume “macOS Sierra” and Internet Install is fine too but still get Sierra. Any advice from the Pros ?

Make sure the version of recovery is less than or equal to the major version of the OS you are trying to install. In recovery, run sw_vers and verify the version.


Thank you Tim,

I tried a couple of different ways in past days and finally figured out the issue and got a workaround:

  • the iMacs (2015 Fusion) all currently have Sierra, we want to upgrade them to Catalina
  • the boot partition ver Sierra is too old to handle the new Catalina MDS image - failed to reboot after downloading ( couyld be the Sierra not supporting APFS well issue ?)
  • so I upgraded the Sierra to High Sierra with a Installer , then run MDS recovery it works fine. This process upgraded the boot partition automatically.
  • To further confirm its a boot partition issue, I tried to upgrade only the Boot Partition on the Sierra with the utility script create_macos_recovery the results are the same - added a little bit time to prepare but all works so far. Thanks for your MDS, its great !