ntp failed to install/upgrade: useradd: cannot lock /etc/passwd; try again later.

[Joshua Lückers]

Binary package hint: ntp

When installing I get the folliwing error:
sudo aptitude install ntp
[sudo] password for joshua:
Reading package lists... Done
Building dependency tree
Reading state information... Done
Reading extended state information
Initializing package states... Done
The following partially installed packages will be configured:
  ntp
0 packages upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
Need to get 0B of archives. After unpacking 0B will be used.
Writing extended state information... Done
Setting up ntp (1:4.2.4p6+dfsg-1ubuntu5) ...
useradd: cannot lock /etc/passwd; try again later.
adduser: `/usr/sbin/useradd -d /home/ntp -g ntp -s /bin/false -u 119 ntp' returned error code 1. Exiting.
chown: invalid user: `ntp:ntp'
dpkg: error processing ntp (--configure):
 subprocess installed post-installation script returned error exit status 1
Errors were encountered while processing:
 ntp
E: Sub-process /usr/bin/dpkg returned an error code (1)
A package failed to install. Trying to recover:
Setting up ntp (1:4.2.4p6+dfsg-1ubuntu5) ...
useradd: cannot lock /etc/passwd; try again later.
adduser: `/usr/sbin/useradd -d /home/ntp -g ntp -s /bin/false -u 119 ntp' returned error code 1. Exiting.
chown: invalid user: `ntp:ntp'
dpkg: error processing ntp (--configure):
 subprocess installed post-installation script returned error exit status 1
Errors were encountered while processing:
 ntp
Reading package lists... Done
Building dependency tree
Reading state information... Done
Reading extended state information
Initializing package states... Done

Description: Ubuntu 9.10
Release: 9.10

ntp:
  Installed: 1:4.2.4p6+dfsg-1ubuntu5
  Candidate: 1:4.2.4p6+dfsg-1ubuntu5
  Version table:
 *** 1:4.2.4p6+dfsg-1ubuntu5 0
        500 http://ubuntu.mirror.cambrium.nl karmic/main Packages
        100 /var/lib/dpkg/status

[Jean-Baptiste Lallement (jibel)]

Thanks for your report.
This is very similar to bug 432964. Check that there's a file called /etc/gshadow.lock, and possibly /etc/shadow.lock, /etc/passwd.lock too; if that's the case, remove them (no risk), and retry. The problem might come from a crash while using the guest session: do you remember such a situation?

[Joshua Lückers (joshualuckers)]

The file /etc/gshadow.lock is not present. /etc/shadow.lock and /etc/passwd.lock are present.
Removing both *.lock file's did the trick.

I do not remember a crash while using a guest session, but my system did indeed crashed once before.

[Jean-Baptiste Lallement (jibel)]

Thanks for following up. I'm marking as duplicate of bug 432964. Don't hesitate to submit any new bug.