Mozilla Firefox allows you to set a master password, which protects your locally stored usernames and passwords. This is a very useful feature specially when you share your computer with someone else. But in case, if you forget the master password, you must reset it.
Warning: Resetting your master password will also remove all of your locally saved usernames and passwords.
To reset the master password follow the steps given below:
1. Start the Firefox, paste following url in address bar – chrome://pippki/content/resetpassword.xul and press Enter
2. “Reset Master Password” page will appear. Click the Reset button and you are done