Here’s how to reset the master password on Firefox so that you can create a new one (and hopefully now forget it this time). Step 1: Launch Firefox and enter chrome://pippki/content/resetpassword.xul location on the address bar and press enter.
Step 2: A warning will be shown and you will be asked to confirm that you want to reset the password. Click on Reset button.
Step 3: A confirmation dialog will appear. Click on Ok and you will be done.
Note: Resetting your master password will remove all of your saved usernames and passwords. Next time you start Firefox you will not be asked for the Master Password. However, you can go ahead and set a new one. 🙂 Image Credit: Freddy
