But what if your master password is lost? You will neither be able to access your existing passwords nor you can use auto-login any more. In this case, you just need to reset the master password by following the below mentioned 3 simple steps:
Open Firefox and enter the following text in the address bar (where you enter website address)
You will then be asked to confirm the password reset.
Read the warning message and press ‘reset’ button.
That’s it! The following the above 3 step procedure, you can easily reset the master password of Mozilla Firefox but do not forget that all the existing passwords stored inside firefox will be deleted. As such on a periodical basis you can backup your passwords using Password Exporter
Related Reading: Password Exporter – Backs Up your Saved Password in Firefox