Does this happen on all pages where you try to login and have an name and password saved?

Start Firefox in Safe Mode to check if one of the extensions (Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem.

• Switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance
• Do NOT click the Reset button on the Safe Mode start window

• https://support.mozilla.org/kb/Safe+Mode
• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

Thank you for your update Cor-el;

>> Does this happen on all pages where you try to login and have an name and password saved?

Nope, this happening for some SSL sites

>> SAFE MODE

When I start my FF in safe mode; the saved username and password not working, it is like a new FF so unable to reproduce the issue.

If it works in Safe Mode and in normal mode with all extensions (Firefox/Tools > Add-ons > Extensions) disabled then try to find which extension is causing it by enabling one extension at a time until the problem reappears.

Close and restart Firefox after each change via "Firefox > Exit" (Windows: Firefox/File > Exit; Mac: Firefox > Quit Firefox; Linux: Firefox/File > Quit)

Some added toolbar and anti-virus add-ons are known to cause Firefox issues. Disable All of them.

I have no anti-virus (I am in linux); and no tool-bar, since this is a fresh installation.

I have tried your steps but it didn't help me :(

Here is one more clue which may help you..

While I started to type my username I am getting an autofill pop up under the username box, if I click there then the username disapperas and I can see password box filled with dots.

If I type the username fully with out using the autofill popup; then no password filled in the password box.

Waiting for your reply.

Open the Password Manager in Firefox and remove all entries for the site.

This issue fixed in FireFox 33. So we can mark this as solved.