Your password needs to be reset.
You have forgotten your password.
You can reset and choose a new password for Ubuntu in five steps:
1. Turn on your computer and if you see the GRUB bootloader press <ESC>
2. Choose the option <Recovery modus> and select <root> (drop to root shell prompt).
3. At the command promt type <passwd> + <your username> (e.g. passwd testuser). If you don't remember your username anymore type <ls / home> at the command promt to show it.
4. Now type your new password two times.
5. Restart your computer with the <shutdown -r now> command.
About the Author
Wim Peeters is electronics engineer with an additional master in IT and over 30 years of experience including time spent in support, development, consulting, training and database administration. Wim has worked with SQL Server since version 6.5. He has developed in C/C++, Java and C# on Windows and Linux in different European countries and different European languages. He writes knowledge base articles to solve IT problems and publishes them on the Lubby Knowledge Platform where he is one of the most important contributors and the main developer.