All of a sudden one day my computer required me to log in before going to my desktop. I put in my password, but it didn't work, and when I tried to fix the problem via the command line, the command line wouldn't accept my password either.

I successfully reset the password twice, just to be absolutely sure I was using the correct password, but it still wouldn't accept the new password after it was successfully changed.

The method I used to change the password was:

mount -o remount,rw /
chmod 640 /etc/shadow
sudo passwd USER
  • When correct password is used it returns to this screen

    login screen, loop with correct password

    and when incorrect password is used, it returns to this screen

    login screen, loop with incorrect password

I followed instructions to mount the root file-system/chroot in live cd/usb, and try chroot with strace -o login.strace login to see if I got different results but I didn't. enter image description here

closed as off-topic by dessert, Videonauth, David Foerster, Eric Carvalho, user117103 Nov 26 '17 at 19:46

This question appears to be off-topic. The users who voted to close gave this specific reason:

  • "This describes a problem that can't be reproduced that seemingly went away on its own or was only relevant to a very specific period of time. It's off-topic as it's unlikely to help future readers." – dessert, Videonauth, David Foerster, Eric Carvalho, guntbert
If this question can be reworded to fit the rules in the help center, please edit the question.

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    Another thought that crossed my mind: perhaps it is not your password that is corrupt, but your user account. Have a look at /var/log/auth.log and search for your username. – Phillip -Zyan K Lee- Stockmann Nov 12 '16 at 9:16
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    @Dpan, I may not much help for you, the login process is new to me. If you have time we may go one by one to debug the problem. You can't login in tty7 (GUI) neither in tty1 (Console), right? But you can still drop to recovery root shell. In recovery shell after remounting / as rw, try login command if can login let me know. If not try again with strace -o login.strace login then upload the login.strace log – user.dz Nov 28 '16 at 11:59
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    @Dpan, Could you update the question instead of comments, such info are important, also the question may get more attention. Follow the instructions in this answer to mount the root file-system/chroot in live cd/usb, but don't run update-grub then after chroot try with strace -o login.strace login see if you get different results. If login.strace created, post it to paste.ubuntu.com – user.dz Dec 7 '16 at 9:14
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    @Dpan, Use the small edit link under the question post & above the comments (exactly below tags). See askubuntu.com/help/editing if you want to learn about its importance. – user.dz Dec 15 '16 at 8:43
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    @Dpan, I can't see what you are facing. Could you edit and include all the output you get, as you are only in recovery, take pictures. – user.dz Dec 17 '16 at 13:01