Press the ''[Shift]'' key during startup to get the Grub2 menu\\
In the menu that follows, select ''Advanced options for Ubuntu''\\
In the subsequent menu, select the topmost option that has ''Recovery Mode''\\
In the Revovery Menu, select ''Root - Drop to root shell prompt''\\
You will get to a terminal window\\
Type ''mount -o rw,remount /'' to mount the filesystem\\
If you don't know the username, type ''ls /home'' to see the user directory name\\
Then type ''passwd username'' where username is the user you are trying to reset the password for\\
It will ask you **twice** for a new passwd. Type in the passwd.\\
Type ''reboot'' to restart the system.


Another webpage has this\\
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By default the first user's account is an administrative account, so if the UI is prompting you for a password it's probably that person's user password. If the user doesn't remember their password you need to reset it. To do this you need to boot into recovery mode.

Boot up the machine, and after the BIOS screen, hold down the left Shift key. You will then be prompted by a GRUB menu.

I've noticed on some systems that timing when to hit the left Shift key can be tricky, sometimes I miss it and need to try it again.

Hit the down arrow until you select the 2nd entry from the top (the one with the recovery mode in the description) and then hit Enter.

Now you should see the Recovery menu:

with resume, clean, dpkg ... etc

Using the arrow keys scroll down to root and then hit Enter.

You should now see a root prompt, something like this:

<code>
root@ubuntu:~#
</code>

At this stage you should have a read-only filesystem. You have to remount it with write permissions:

<code>
mount -o rw,remount /
</code>

Now we can set the user's password with the passwd command. (In this example I will use jorge as the example, you need to substitute whatever the user's username is):

<code>
root@ubuntu:~# passwd jorge
Enter new UNIX password:
Retype new UNIX password:
passwd: password updated successfully
root@ubuntu:~#
</code>

Type in what you want the new password to be at the prompt. After it's successful reboot the machine and the user will be able to log in with their new password.

