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Georgios
Asked: 2021-04-10 05:54:36 +0800 CST

System administration: Password incorrect

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I have installed Ubuntu 18.04.5 beside Windows10 (after Windows10). The Ubuntu-System runs properly, but I cannot install Software or refresh the System. "Sudo" requests for the administrator password, as all other system- related actions. Means, I have no chance to reach the administrator platform (#). Always the message: Wrong password, but I use the right password. What can I do? Thanks.

password

1 Answers

  1. Note: First to be clear, sudo requires the password of the user that wants super user to do something. Sudo's password is separate from root's password. The user must also be part of that OSs super user group. In Ubuntu that is "sudo"

    Usual things to check are: Is/was caps lock active during password entry and if you usually do not use the US keyboard layout, if you might have entered a different password than you thought. Consult a us keyboard1 an retrace what you might have entered.

    If that does not help, an option to recover access is to boot your system with a Live-CD and mount your root partition. An Ubuntu install disk will do. During boot up select "try" Ubuntu. From there you will need to discover your root partition.

    [Rought steps]
$ sudo -s
# fdisk -l (discover your root partition, possibly by its specific size, filesystem)
# mkdir other_root
# mount /dev/your_root_partition other_root
# chroot other_root

(Option A: You know your password, but not part sudo group)
# usermod -a -G sudo your_username

(Option B: You are part of sudo group, but don't know your password)
# passwd your_username

-All done and reboot-

    If in doubt, your just mount a suspected root partition and look around. If it contains folders like etc, usr, mnt then its likely your root partition.

    There are also other ways to regaining root access with a Live-CD, like editing /etc/shadow file to reset password, or directly adding your user to /etc/sudoers, but using chroot might be the easier way.

    US Keyboard Layout

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