How to Reset Master Password in Mozilla Firefox
Mozilla Firefox can protect your saved certificates and passwords with a master password. If you want to reset the master password, you can simply provide the current password and reset it to a new one. However, if you forget your master password then you are in trouble and will not have the option to change the existing password.
You can reinstall Firefox over an existing version, or you can even remove Firefox completely and reinstall a fresh copy, you still will not be able to reset the master password. But here’s a method that you can use to reset the master password in Firefox. Type the following command in the address box in your browser and then click the reset button in the lower right corner, as shown in the graphic.
If you run into a situation where the above method does not work, then you may need to hack the password using a Firefox master password recovery tool, such as FireMaster.