Change User Password
If you can't log into your computer, you can follow these instructions to reset the password for any user. Pop!_OS and Ubuntu allow for the root user to reset the password for any user account. In order to get to the root user, we need to restart the computer and use what's called "single user mode", which is the low level repair system for the computer.
Pop!_OS 18.04 and Later
On a fresh install Pop!_OS 18.04 and later, systemd-boot is used rather than GRUB. Please follow these instructions to reset your password. If your operating system is anything other than Pop!_OS 18.04 and later, please use the GRUB section.
First, bring up the systemd-boot menu by holding down SPACE or the ESC key. On the menu, choose Recovery Mode.
Once the recovery operating system boots, close out of the installation window or choose “try demo mode” (be sure not to choose any install or repair options, as this could result in data loss).
Mounting the Installed OS
Press /+T to open a terminal, and type in these commands:
This will show what the main internal drive is named, which will have 4 partitions on it. We will be working with the 3rd partition. If the main drive is an NVMe drive, it will be
/dev/nvme0n1p3 and if the drive is a SATA or regular M.2 drive, it will be
Next, run this command:
sudo mount /dev/sda3 /mnt
If the command fails and says
mount: /mnt: unknown filesystem type 'crypto_LUKS', then the hard drive has been encrypted, and additional commands are needed to unlock it. If the command succeeds (no output), then skip these next steps:
sudo cryptsetup luksOpen /dev/sda3 volume sudo lvscan sudo vgchange -ay
Take note as to what the volume group is called, substituting the correct info into this command. Make sure that '-root' is on the end:
sudo mount /dev/mapper/data-root /mnt
Next, regardless of whether the drive is encrypted or not, run these commands:
sudo chroot /mnt ls /home
Take note of the users on this computer, then run this command to change a user's password:
Type in your new password, and then enter these commands:
Now, enter the original passphrase. Here you will be prompted for the new passphrase, and then to confirm the new passphrase.