I have installed Nvidia drivers then I restarted the laptop. When I typed exit on root@name:~# terminal, the following message appears in red:

Failed to start default target: Transaction for.graphical.target/start is destructive (emergency.target has ‘start’ job queued, but ‘stop’ is included in transaction)

screenshot showing the error message

Can I downgrade to default graphics drivers using the terminal?


1 Answer 1


This is probably too late for you, but I just helped a friend with this same issue. The solution was simple. It has to do with a disk not being able to be mounted.

In your case in particular and looking at your included image, I can not see the very first lines that it printed out, which would be helpful--it tells which disk is not able to be mounted.

In my friend's case, in the /etc/fstab file, there was an extra entry for an external USB hard drive. For some reason, the system wasn't able to find it at boot, and it caused this same draconian message that you're getting.

The solution was simply to edit the file using sudo nano /etc/fstab and put a # at the start of the relevant line to prevent the line from being active. Reboot and computer should start up normally.

This whole thing happened when updating Kubuntu 20.04 to 22.04.

  • thanks, you saved my life
    – Thinh NV
    Dec 26, 2023 at 2:52
  • 1
    Yes this was the case for me, too. I had a iscsi -mount not mounted. For me the solution was to run in the recovery console: mount -a Feb 17 at 9:16
  • Thanks, the mount -a really helped. Just a sidenote that might be relevant, I was worried about commenting the /boot/efi partition, but it was not an issue.
    – Enzo Dtz
    Feb 19 at 7:16
  • You saved my life. I almost go crazy about this error and not being able to boot. Then I did this and found an entry for a partition I deleted yesterday. I can breathe again. Thanks Mar 12 at 15:21

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