POSSIBLY SOLVED Reverting to login screen

[Bari]

I am having an intermittant problem in that when filling in online forms pressing the shift key and one of the numeric keys along the top row the screen turns black and then reverts to the login splash screen. Is some combination of keys that will do this, are my fingers to big and I'm accidentally pressing more that one key at a time. I have tried to replicate the fault but don't seem to be able to. Any ideas please.

[remoulder]

Please look through your system log files (menu | Administration | Log File Viewer) around the time this happen to see if there are clues there.

[Bari]

Thanks for the reply. It did it again today but this time when I pressed the enter key.
syslog reads

Jun 9 18:54:18 barry-desktop pulseaudio[1677]: ratelimit.c: 7 events suppressed
Jun 9 18:56:12 barry-desktop init: tty2 main process ended, respawning
Jun 9 18:56:56 barry-desktop gnome-session[1612]: WARNING: Detected that screensaver has left the bus
Jun 9 18:56:56 barry-desktop gdm-simple-slave[1910]: WARNING: Unable to load file '/etc/gdm/custom.conf': No such file or directory
Jun 9 18:56:56 barry-desktop acpid: client 1066[0:0] has disconnected
Jun 9 18:56:56 barry-desktop acpid: client connected from 1914[0:0]
Jun 9 18:56:56 barry-desktop acpid: 1 client rule loaded
Jun 9 18:56:57 barry-desktop acpid: client connected from 1914[0:0]
Jun 9 18:56:57 barry-desktop acpid: 1 client rule loaded
Jun 9 18:56:57 barry-desktop gdm-session-worker[1951]: WARNING: Unable to load file '/etc/gdm/custom.conf': No such file or directory
Jun 9 18:56:58 barry-desktop rtkit-daemon[1447]: Sucessfully made thread 1957 of process 1957 (n/a) owned by '114' high priority at nice level -11.
Jun 9 18:56:58 barry-desktop rtkit-daemon[1447]: Supervising 1 threads of 1 processes of 1 users.
Jun 9 18:56:58 barry-desktop rtkit-daemon[1447]: Sucessfully made thread 1959 of process 1957 (n/a) owned by '114' RT at priority 5.
Jun 9 18:56:58 barry-desktop rtkit-daemon[1447]: Supervising 2 threads of 1 processes of 1 users.
Jun 9 18:56:58 barry-desktop rtkit-daemon[1447]: Sucessfully made thread 1960 of process 1957 (n/a) owned by '114' RT at priority 5.
Jun 9 18:56:58 barry-desktop rtkit-daemon[1447]: Supervising 3 threads of 1 processes of 1 users.
Jun 9 18:56:59 barry-desktop gdm-simple-greeter[1948]: Gtk-WARNING: /build/buildd/gtk+2.0-2.20.1/gtk/gtkwidget.c:5636: widget not within a GtkWindow
Jun 9 18:57:09 barry-desktop init: tty2 main process ended, respawning
Jun 9 18:57:09 barry-desktop gdm-session-worker[1951]: GLib-GObject-CRITICAL: g_value_get_boolean: assertion `G_VALUE_HOLDS_BOOLEAN (value)' failed
Jun 9 18:57:14 barry-desktop gdm-session-worker[1951]: pam_sm_authenticate: Called
Jun 9 18:57:14 barry-desktop gdm-session-worker[1951]: pam_sm_authenticate: username = [barry]
Jun 9 18:57:15 barry-desktop rtkit-daemon[1447]: Sucessfully made thread 2055 of process 2055 (n/a) owned by '1000' high priority at nice level -11.

and I also found in the Auth.log

Jun 9 18:43:16 barry-desktop gdm-session-worker[1437]: pam_succeed_if(gdm:auth): requirement "user ingroup nopasswdlogin" not met by user "barry"
Jun 9 18:43:23 barry-desktop gdm-session-worker[1437]: pam_unix(gdm:session): session opened for user barry by (uid=0)
Jun 9 18:43:23 barry-desktop gdm-session-worker[1437]: pam_ck_connector(gdm:session): nox11 mode, ignoring PAM_TTY :1
Jun 9 18:43:23 barry-desktop polkitd(authority=local): Registered Authentication Agent for session /org/freedesktop/ConsoleKit/Session2 (system bus name :1.34 [/usr/lib/policykit-1-gnome/polkit-gnome-authentication-agent-1], object path /org/gnome/PolicyKit1/AuthenticationAgent, locale en_GB.utf8)
Jun 9 18:56:33 barry-desktop login[1890]: pam_unix(login:auth): bad username [-]
Jun 9 18:56:36 barry-desktop login[1890]: FAILED LOGIN (1) on '/dev/tty2' FOR 'UNKNOWN', Authentication failure
Jun 9 18:56:56 barry-desktop gnome-keyring-daemon[1594]: dbus failure unregistering from session: Connection is closed
Jun 9 18:56:56 barry-desktop gnome-keyring-daemon[1594]: dbus failure unregistering from session: Connection is closed
Jun 9 18:56:56 barry-desktop polkitd(authority=local): Unregistered Authentication Agent for session /org/freedesktop/ConsoleKit/Session2 (system bus name :1.34, object path /org/gnome/PolicyKit1/AuthenticationAgent, locale en_GB.utf8) (disconnected from bus)
Jun 9 18:56:56 barry-desktop login[1890]: pam_securetty(login:auth): unexpected response from failed conversation function
Jun 9 18:56:56 barry-desktop login[1890]: pam_securetty(login:auth): cannot determine username
Jun 9 18:56:56 barry-desktop login[1890]: pam_nologin(login:auth): cannot determine username
Jun 9 18:56:56 barry-desktop gdm-session-worker[1437]: pam_unix(gdm:session): session closed for user barry
Jun 9 18:57:00 barry-desktop login[1890]: FAILED LOGIN (2) on '/dev/tty2' FOR 'UNKNOWN', Error in service module
Jun 9 18:57:00 barry-desktop login[1890]: pam_securetty(login:auth): unexpected response from failed conversation function
Jun 9 18:57:00 barry-desktop login[1890]: pam_securetty(login:auth): cannot determine username
Jun 9 18:57:00 barry-desktop login[1890]: pam_nologin(login:auth): cannot determine username
Jun 9 18:57:02 barry-desktop login[1890]: FAILED LOGIN (3) on '/dev/tty2' FOR 'UNKNOWN', Error in service module
Jun 9 18:57:02 barry-desktop login[1890]: pam_securetty(login:auth): unexpected response from failed conversation function
Jun 9 18:57:02 barry-desktop login[1890]: pam_securetty(login:auth): cannot determine username
Jun 9 18:57:02 barry-desktop login[1890]: pam_nologin(login:auth): cannot determine username
Jun 9 18:57:06 barry-desktop login[1890]: FAILED LOGIN (4) on '/dev/tty2' FOR 'UNKNOWN', Error in service module
Jun 9 18:57:06 barry-desktop login[1890]: pam_securetty(login:auth): unexpected response from failed conversation function
Jun 9 18:57:06 barry-desktop login[1890]: pam_securetty(login:auth): cannot determine username
Jun 9 18:57:06 barry-desktop login[1890]: pam_nologin(login:auth): cannot determine username
Jun 9 18:57:09 barry-desktop login[1890]: FAILED LOGIN (5) on '/dev/tty2' FOR 'UNKNOWN', Error in service module
Jun 9 18:57:09 barry-desktop login[1890]: TOO MANY LOGIN TRIES (5) on '/dev/tty2' FOR 'UNKNOWN'
Jun 9 18:57:09 barry-desktop login[1890]: pam_mail(login:session): cannot determine username
Jun 9 18:57:09 barry-desktop login[1890]: pam_unix(login:session): close_session - error recovering username
Jun 9 18:57:09 barry-desktop login[1890]: Error getting passwd info for user [(null)]; rc = [19]
Jun 9 18:57:09 barry-desktop gdm-session-worker[1951]: pam_succeed_if(gdm:auth): requirement "user ingroup nopasswdlogin" not met by user "barry"
Jun 9 18:57:14 barry-desktop gdm-session-worker[1951]: pam_unix(gdm:session): session opened for user barry by (uid=0)
Jun 9 18:57:14 barry-desktop gdm-session-worker[1951]: pam_ck_connector(gdm:session): nox11 mode, ignoring PAM_TTY :1
Jun 9 18:57:15 barry-desktop polkitd(authority=local): Registered Authentication Agent for session /org/freedesktop/ConsoleKit/Session4 (system bus name :1.62 [/usr/lib/policykit-1-gnome/polkit-gnome-authentication-agent-1], object path /org/gnome/PolicyKit1/AuthenticationAgent, locale en_GB.utf8)

To me the incident seemed to happen at 18.56.33 and although the log states 5 tries to log on all that happened was the screen went black the instant the enter key was pressed and after a short time the logon screen came up and I logged on again,

I have also posted this on linuxformat.co.uk asking would going to auto logon fix this? have also found a 3 week old post on the ubuntu forum with sort of the same problem but no solution to it.
Hope the logs help.

[remoulder]

Do you have automatic login enabled? If so try turning it off and entering your password. If this works report a bug at https://bugs.launchpad.net/community.linuxmint.com

[vincent]

You sure you didn't press CTRL + ALT + BACKSPACE, right? Yeah, I know, it's a stretch...but you say you do have big fingers, right?

Try disabling the restart X keyboard shortcut in your keyboard layout options and see if this happens any more.

[Bari]

Ok, I didn't have auto log on enabled so I enabled it but the problem is still persisting. have now disabled the kill Xserver option in keyboards as suggested. Its just done it again on inputting the number 2 into a online form.

[Bari]

I think I may have resolved this, after reading countless forum posts i found a mention that sometimes when X crashes the login screen comes up. So investigating I found that I had installed the 173 Nvidia driver instead of the the recommended one. So uninstalled 173 and installed the other one and so far (two days) have had no problems.