Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

Two days ago Firefox started throwing strange javascript errors e.g.

Error: Cc[contractID] is undefined
Source File: file:///C:/Program%20Files/Mozilla%20Firefox/components/nsLoginManager.js
Line: 113

It's throwing these on every page on every site I visit.

If I browse to a site that requires http authentication (e.g. - one of our test sites), the authentication dialog no longer includes the "Remember this password" checkbox, even though I'm not in Private Browsing mode, and "Remember passwords for sites" is still ticked in the Firefox options. It also throws an even bigger javascript error:

Error: LoginManagerPrompter: Epic fail in promptAuth: [Exception... "'[JavaScript Error: "Cc[contractID] is undefined" {file: "file:///C:/Program%20Files/Mozilla%20Firefox/components/nsLoginManager.js" line: 113}]' when calling method: [nsILoginManager::findLogins]"  nsresult: "0x80570021 (NS_ERROR_XPC_JAVASCRIPT_ERROR_WITH_DETAILS)"  location: "JS frame :: file:///C:/Program%20Files/Mozilla%20Firefox/components/nsLoginManagerPrompter.js :: anonymous :: line 585"  data: yes]

Source File: file:///C:/Program%20Files/Mozilla%20Firefox/components/nsLoginManagerPrompter.js
Line: 607

If I view saved passwords in the Firefox options dialog, there are none.

I've deleted my key3.db and signons.sqlite files from my profile, but that didn't help.

These errors continue if I run Firefox in safe mode, so I don't think it's related to any of my add-ons. I'm running Firefox 3.6.6 on Vista SP2.

Any ideas?

share|improve this question
up vote 1 down vote accepted

Maybe your FF installation is simply corrupt. Have you tried reinstalling FF? This will leave your profile folders untouched, so no settings should be lost (you only need to reinstall addons that were installed for everyone).

If you are curious, you could also backup your old files under Program Files/Mozilla, and compare them after the reinstall.

share|improve this answer
Thanks sleske - that's done it. Note to self: try the simple fixes first! I wonder what could have happened to corrupt it like that? – Mark B Jul 21 '10 at 9:04

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.