I'm sorry this post is so long, but I wanted to make sure that all the stuff that might be relevant was readily available.

I've been trying to create a new user account on my laptop, and, even though I tried everything I found online, I'm still not able to do it. I would like to remark that I was not using uppercase letters (which seems to be the reason why some other users could not create a new account on the questions I checked).

First of all, I tried to create an account in GUI mode. After entering the new username on the account creation dialog I get this message:

running '/usr/sbin/adduser' failed: Child process exited with code 1

After some googling I downloaded gnome-system-tools from the Ubuntu Software Centre. I enter all the data on the "Create New User" dialog and this is what I get:

The configuration could not be saved
Invalid data was found.

That's when I decide to open the terminal and see what was going on. I enter the command sudo adduser newuser I get this:

adduser: The group `newuser' already exists.

so I delete the group using the command sudo delgroup newuser, and use the previous command again. After doing so, I get this:

Adding new group 'newuser' (1001) ...
Adding new user 'newuser' (1001) with group 'newuser' ...
useradd: existing lock file /etc/subgid.lock without a PID
useradd: cannot lock /etc/subgid; try again later.
adduser: '/usr/sbin/useradd -d /home/newuser -g newuser -s /bin/bash -u 1001 newuser' returned error code 18. Exiting.

Again, the newuser group is created, but not the user. However, when using the useradd command instead of adduser, I just get the two useradd lines above and no group is created. In neither case I'm able to create a new user. I also tried all these commands opening the terminal as root and it was useless. What should I do now?

Edit: I rebooted the machine twice, and repeated the process using the terminal as root. It did not work.

  • 1
    Have you tried rebooting your machine? – s3lph Dec 30 '14 at 23:22
  • @the_Seppi Oh, yes. Twice. – Tipsy Triceratops Dec 30 '14 at 23:25
  • Try removing the file /etc/subgid.lock. It seems like some process using this lock crashed or didn't work correctly (e.g. a faulty package installation/removal script) – s3lph Dec 30 '14 at 23:28
  • @the_Seppi Thank you! It worked :) (I had to remove it using the terminal as root, though). – Tipsy Triceratops Dec 30 '14 at 23:34
  • It might also be worthwhile running sudo pwck -q to see if the files have been left in an inconsistent state – steeldriver Dec 30 '14 at 23:36

Since there's a warning about some lockfile, I assume that some process who changed user or group information failed at some point and the file persisted.

First check, whether a process still claims this file: fuser /etc/subgid.lock. If nothing is returned, you can safely remove this file sudo rm /etc/subgid.lock.

Then it should work again.

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