Unknown Master Password is Set at Initial Startup (Firefox)

This procedure works on Win XP, for what it's worth. I didn't test it on *nix.

Problem:

Upon initial installation, Firefox apparently believes it has a non-null Master Password in effect, and the user is unable to change it using..

Tools->Options->Privacy->Saved Passwords->Change Master Password

..because said Master Password is unknown to the user (1) (2).

Note: This situation may only occur when one imports an existing Mozilla suite profile's passwords at Firefox install time, but I'm not sure.

Solution:

Shut down Firefox.

Rename..

\Documents and Settings\<user>\Application Data\Mozilla\Firefox\Profiles\xxxxxxxx.default\key3.db

..to some different name, e.g. key3.db.orig.

Then, if you want to actually set a Master Password you can use, re-launch Firefox, and use either..

Tools->Options->Privacy->Saved Passwords->Change Master Password

..or the..

chrome://pippki/content/pref-masterpass.xul (3)

..dialogs to enter your desired password.

Otherwise, re-launch Firefox, and the insidious unknown default Master Password ought to now be disabled. Someone please test this.

References:

(1) master password problem-can I reset it?

(2) Avoid master password when filling in site passwords????

(3) Firefox : FAQs : Master password settings