I have 12.04 and have 2 printers installed, both wirelessly over my personal network, no printer sharing. When I try to modify the printers I get a window asking for authentication (username and password). For the life of me I cannot think what these might be. At first I thought it might be my Ubuntu account username and password, but I can't get it to work. The printer username and password (admin and access) doesn't work either.

Does anyone know what it is asking for, and how I can turn that off?

Many thanks.

  • 1
    try the username & password which was set up first (when installing Ubuntu)
    – Uli
    Apr 9, 2013 at 17:25

3 Answers 3


You might be affected by this bug.

Try running

gksudo system-config-printer

in a terminal window, then setting up the printer

However, if gksudo is not found, try:

sudo -H system-config-printer
  • Tried in Ubuntu 12.4.2 and it works. Thanks! May 29, 2013 at 17:19
  • Tried in Ubuntu 13.10 and it works too.
    – raphie
    Mar 29, 2014 at 3:44
  • I've tried that with the following results:-
    – hal_v
    Apr 30, 2018 at 21:27
  • Sorry these results:-(system-config-printer:3620): Gtk-CRITICAL **: 07:26:04.797: gtk_tree_store_insert_after: assertion 'G_NODE (sibling->user_data)->parent == G_NODE (parent->user_data)' failed (system-config-printer:3620): Gtk-CRITICAL **: 07:26:04.797: gtk_tree_store_set_value: assertion 'VALID_ITER (iter, tree_store)' failed (system-config-printer:3620): Gtk-CRITICAL **: 07:26:04.797: gtk_tree_store_set_value: assertion 'VALID_ITER (iter, tree_store)' failed
    – hal_v
    Apr 30, 2018 at 21:27

Adding my username to the lpadmin group, as suggested by msanderz, worked for me. Here is how you add yourself to the group:

sudo usermod -a -G lpadmin YOUR_USERNAME

I had a similar problem and solved it by adding my user name to the group "lpadmin" which allowed me to make changes in the printer. Since I have been trying to solve a different problem for about three days I do not remember exactly what I did. Try googling "ubuntu add user name to groups" for the sudo command to add your user name.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .