hello, are you the only user accessing those machines? using a different, but up-to-date browser would certainly be a better idea, than sticking with firefox 12 anyway: https://www.mozilla.org/security/known-vulnerabilities/firefox.html

Which XP service pack do you have?

Note that you also have a very old flash 9 version:

1. Shockwave Flash 9.0 r280

• https://support.mozilla.org/kb/Managing+the+Flash+plugin
• http://kb.mozillazine.org/Flash

I run more than a dozen Firefox installations and have never had Firefox update all by itself.

Exactly how are you disabling the Firefox app update?

I fail to see how the number of people using these PC's has anything to do with preventing Firefox from updating. No one would fool about with update features.

I can cope with any security issues without migrating to a new browser -- either a new flavor-of-the-month Firefox or e.g., Opera.

if there are multiple user accounts on a machine, the settings regarding to auto-update you set in your profile won't automatically apply to other accounts - so they still might be set to automatically update...

I don't use XP on all PC's -- I run several OS'. For the ones with XP, SP2-3, depending. Same result on all; Firefox gets up one morning and upon opening the browser decides to update itself. Might as well be using some sort of AppleCrap what with all the control I'm being allowed on my own systems. I do note that if I get screwed about on one PC and wait a day or so, none of the others update. That is one clue that makes me believe that this is caused by something at Mozilla offices, overriding any options I check on Firefox(s).

Ah, got that. Thx.

No, only one "user" account on any system.

So, you are implying that an older version of Flash (i.e., which is also not allowed to update) would allow Firefox to update itself? Odd.

I can't tell you precisely how I prevented updates in the older version since I'm now dealing with the newer, unwanted version. Nonetheless, I go to Options/Advanced/ ___ "never check for updates". Sounds similar to what I'd used previously. There is also a WinSilentUpdate option that can be disabled, but, I'm not going there to revisit until I've taken the time to uninstall and reinstall my preferred version of Firefox. This is the last time I'm going thru all this so I want to take the time to do it right.

Why are you insisting on using ancient versions? You need to run a modern version, or use a different browser. Running old browsers leaves you open to all the holes listed at https://www.mozilla.org/security/known-vulnerabilities/firefox.html

Please update not only your Firefox, but your plugins (like Flash) and your operating system's updates.

Using the UI preferences in Options > Advanced -> Update isn't the most reliable way of keeping Firefox from updating. Plus, the basic prefs for controlling of the "app", extensions, and search plugins really hasn't changed in like 8 years, only the user interface.

This code placed in a user created user.js file is what I have been using for 8 or 9 years. I still have Firefox 2.0.0.20 installed on this PC for one specific activity, and it hasn't updated since 2008-12-18 when Firefox 2.0.0.20 came out, and I did a manual update to the final 2.0 version.
http://kb.mozillazine.org/User.js_file

// turn off application updates:
user_pref("app.update.enabled", false); 

As mentioned by philipp, each logon user account has its' own Profile so that code needs to be in each Profile on each PC - including each Profile in the same logon user account. Non-default / user set preferences aren't part of Firefox program files, those "customizations" are saved in the Profile folder.

And as Tyler Downer (and philipp) mentioned, older versions are more vulnerable to being exploited than the latest version is.

WinSilentUpdate shouldn't have any affect on whether Firefox updates or not; typically 3rd party applications use their own update mechanisms, not Microsoft Windows update services.

edit - create your user.js file once and then copy that file into every Profile on each of those computers. And if / when you create a new Profile copy that file into the new Profile. I do that with all the common changes that I make in about:config to save me time when I set up a new PC or create a new Profile. Currently I have 18 preferences set in my user.js file.

To TD, Whilst the latest fad might label my choice "ancient", I choose to retain what works for me. If there is risk, I'll accept that. What turns me off on "latest&greatest vendor brainfart" is that in most cases they are usually just bells and whistles. No value. Just bloat. And, it looks like newest have features designed to limit my choices -- like an auto update as default or it can't even be turned off. You really a fan of throwing out the old and getting the latest&greatest ? Throw the idea down in front of your wife. Suggest you "need" someone new. Imply that she is ancient and you want someone better. It'll be a short conversation; unless you are very, very quick on your feet.

software as old as the versions you are using really is ancient, there is no comparison to anything in the physical world. Not only are the technologies supported by that old version outdated (Forcing web developers to use old technology to build websites and support a wider range of browser versions, thus holding back the whole web), you are leaving yourself wide open to gaping security holes that are publicly known and often exploited. There is a ton of value in the new versions, ask anyone with knowledge of the internet and browsers, and updating isn't an option anymore, just from a security standpoint.

There was an old version of Internet Explorer 6, which has been holding back the internet as a whole for a very long time because users don't update. The same holds true with old versions of Firefox. Not updating is being a bad web citizen and your decisions impact the entire internet.