-> click Firefox button and click Options (or File Menu -> Options)

• Privacy tab -> History section -> under Firefox will: select "Use Custom Settings for History"
  • Remove Checkmark from Permanent Private Browsing mode
  • place Checkmarks on 1) Remember my Browsing History 2) Remember Download History 3) Remember Search and Form History 4) Accept Cookies from sites -> 5) Accept Third-party Cookies -> under Keep Until : select They Expire -> Now click Exceptions button and click Remove button for all website entries which have status set to other than Allow -> Type addresses of websites whose Cookies you want to be stored by Firefox e.g. mail.live.com , login.live.com , hotmail.com , msn.com , mail.yahoo.com , login.yahoo.com , yahoo.com , mail.google.com , google.com , etc. & click Allow button for each of these websites (One by One) -> click Close
  • Remove Checkmark from Clear History when Firefox Closes

• Security tab -> place Checkmark on Remember Passwords for sites -> click Exceptions... button and click Remove All button -> click Close

-> Click OK on Options window

-> IF your Username & Password is already stored by Firefox, you need to Delete it

• Deleting Passwords

-> IF your Username & Password is not currently stored by Firefox yet, go to the Website

• Enter Username & Password
• on the website, place Checkmark on Keep Me Signed-in or Remember Me option
• click Log-in or Sign-in button
• Firefox will ask if you want Firefox to Remember your Username & Password on this site (attached screenshot)
• click the Remember Password button

Check and tell if its working.

-> IF you use Clear Recent History feature, DO NOT select Cookies, Forms and Search History, Active Logins, Site Preferences

• Clear Recent History - What things are included in my history?

-> IF you use Privacy Cleanup softwares like CCleaner etc., DON'T SELECT FIREFOX IN ITS SETTINGS. These softwares can be responsible for Deleting your Firefox Settings.

mha007, thanks for the reply, but that does not address my problem. You suggested:

"-> IF your Username & Password is already stored by Firefox, you need to Delete it

   Deleting Passwords "

That is exactly what I want to avoid. Earlier versions of Firefox gave me the option to change an existing saved password if I overrode the pre-filled value in the password dialog box, I want to figure out how to get back that behaviour.

Try using the Saved Password Editor extension which allows you to edit existing passwords and add new ones manually.
https://addons.mozilla.org/en-US/firefox/addon/saved-password-editor/

the-edmeister, thanks for the reply, but again, that does not solve my problem. I am looking for the seamless experience that earlier versions of Firefox had -- you didn't need to do anything manually, the first time you entered a different password, it would ask you whether you wanted to change it, just like how it asks you whether you want to save it when you first enter it.

It is a particular issue for me as I access a number of sites that have mandatory time-based password change requirements, I change my passwords on a regular basis.

It looks like I might have to file a Bugzilla entry for this as this feature really seems to have got dropped.

Do you see the key icon on the location bar?
Does that only happen with that website?

Make sure that you do not run Firefox in permanent Private Browsing mode.

• https://support.mozilla.com/kb/Private+Browsing

The website may be using autocomplete=off to prevent Firefox from saving the name and password. You can remove autocomplete=off with a bookmarklet to make Firefox save the name and password.

• http://kb.mozillazine.org/User_name_and_password_not_remembered

Start Firefox in Diagnose Firefox issues using Troubleshoot Mode to check if one of the extensions or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox (Tools) > Add-ons > Appearance/Themes).

• Don't make any changes on the Safe mode start window.
• https://support.mozilla.com/kb/Safe+Mode

Ah cor-el, while you didn't solve my problem, your suggestion to check multiple sites helped -- I think I may have narrowed down the problem.

When I use an actual web form to enter the password, I get the option to update the saved password when I change it (checked on support.mozilla.org and at other sites).

But, I use the browser to access a number of internal HTTP SVN repositories which authenticate via LDAP. In those cases, there is no form in which to fill the password, there is typically a pop-up dialog from the SVN server for the password. The problem is that while Firefox is able to fill out that pop-up correctly, it doesn't ask me whether to update the stored password or not in case I change it.

I'll edit the post title and topic appropriately.

Any ideas?

Does Firefox offer to store the new password if you remove the currently stored password?

• Tools > Options > Security: Passwords: "Saved Passwords" > "Show Passwords"

I was having this same problem and was able to solve it for my situation. This problem was happening for me only after moving to a new laptop and downloading Firefox to it. I migrated all of my Firefox information to the new laptop and passwords were working just fine until I changed one of them. That's when this issue occurred - I would change the password to get it, but was not prompted by Firefox to update the password as I always had been in the past. So, I went to the Security area in Options to look at the Saved Passwords and noticed that 'Remember Passwords for Sites' was NOT checked. I checked it, ran a test where I changed a password, and WAS prompted by Firefox to update the password. So, for me, the issue was this setting was different on my new laptop/install vs what I had on the former one.

OK, I feel like an idiot. Turns out that the HTTP server was in the exception list, but under its raw 192.168.X.X IP address rather than under our internally resolved SVN server's host name. I'd missed that as I'd been looking for the host name. Once I removed the IP address entry from the exception list, problem was solved.