Answer by Tmu for Reset the password in Ubuntu / Linux Bash in Windows

• Run bash and make a note of your Linux username (this need not match your Windows username), see How can I find out my user name?
• Close Bash on Ubuntu if it is running (or the next command will fail).

• In Windows admin command prompt (Super+X, A) change the default user to root:

  ubuntu config --default-user root

If you are using Ubuntu 18.04 in WSL, the command has changed to ubuntu1804 , so

ubuntu1804 config --default-user root

• Now Bash on Ubuntu on Windows logs you in as root without asking password

• Use passwd command in Bash to change the user password (the user whose password you want to reset):

  passwd your_username

• Change the default user back to your normal user in Windows command prompt

  ubuntu config --default-user  your_username

If you are using Ubuntu 18.04 in WSL, the command has changed to ubuntu1804 , so

ubuntu1804 config --default-user your_username

Watch Full Video to Recover your password Windows Subsystem Linuxhttps://youtu.be/dTR232yvDCE

Note 1: The subsystem used in the video is not Ubuntu, but Kali Linux. Hence the difference in the command.

Note 2: If you are still using the original Ubuntu subsystem that came with the Anniversary Update, use the command lxrun. Upgrade to the subsystem version distributed via Microsoft Store is recommended.)