Installed a new user and then tried to create one with the name root, because sudo nerves. Didnot work and i have learnt in the meantime, this is not possible.
I am now unable to login into user "admin". It complains that /home/marek/.ICEauthority could not be updated.
I have another user which can login. sudo under the new user does not work and it complains a unsuccessful attempt has been reported.
How can I fix the .ICEAuthority permissions to use this login? > SOLUTION: First log in on terminal with ctrl+alt+F1 as admin, so this was possible, only on destop not. Second gave me all rights in /home/marek back with boldsudo chmod -R u+rw /home/marek. For me it seems, that the error message shows .ICEauthority file and there no rw-rights for admin, but really during my triing to create a root-account ubuntu has deleted my admin-rights somewhere else, because i was still admin and could change user-accounts and have given back only me all rw-rights. Sounds a little bit strange.