Firefox for Enterprise Community Forum

Hello Everyone,

I am seeking assistance to configure Firefox browser so that internet access is blocked when the browser cannot download or access the proxy Auto-configuration (PAC) file. Our organisation enforces all web traffic through proxy servers defined by a PAC file. For compliance and security reasons, users should not have any direct internet access unless the browser is able to successfully retrieve and apply the PAC file.

The desired behaviour is:

1. Firefox attempts to download the PAC file from a defined URL. 2. If the PAC file is unreachable or fails to load (e.g., due to network restrictions or the device being outside the corporate network), Firefox should "fail closed" - meaning it should not allow any direct internet traffic. 3. This is effectively a "fail-block" mode: no fallback to direct connections, and no cached or bypassed proxy settings should allow internet browsing.

This behaviour is critical to prevent devices from accessing the internet without applying corporate proxy rules. I would like to know:

1/ Whether Firefox currently supports a setting or policy that enforces this fail-block condition when the PAC file is unavailable. 2/ If not, whether there are recommended configurations or enterprise policies (e.g., via `policies.json` or Group Policy templates) that could achieve equivalent enforcement.

Thank you for your assistance and guidance.

Hi,

I have 2 machines (Win10 and Win11) with FF 140.3.1esr (32-bit) installed which demonstrates the same failure when I enter one site's url:

PR_CONNECT_RESET_ERROR

Chrome at the same machines goes at this url w/o any failures. Any ideas what to change on "about:config" in FF to allow it opening this url w/o such error?

Hello

We want to set up a GPO that when users exit their Firefox browser, all of there cookies and cache gets deleted.

How do we do this?

Thanks

Hi all,

For quite a while I'm working together with others on a voluntary base (nobody gets money) as members of a computer-club, a charitable NGO and NPO (in German: gemeinnütziger Verein) for seniors in order to bring them closer to the use of digital devices and media. It's not only teaching, but administrating the hard- and software as well.

I can remember that it was possible in former versions of Firefox to include at least a script into "defaults->prefs". I think it was user.js (not sure) in the installation folder to define common preferences to be fixed, like proxi settings. It always worked well, preventing non-privileged users from making any unwanted changes. As a I found out there must have been a very similar way to include add-ons (like uBlock Origin).

Unfortunately all content I found was older than about 10 years. When trying setting up Firefox as it is now, my test system didn't care about anything I've tried.

I'm talking about > 50 Windows-PC having in average 3 user profiles each (for teaching more than 400 members). We are amateurs regarding PC administration, except some network ex-professionals. "Baking" installation media including our needs, as I already found on Mozilla's pages, seems to be beyond our abilities as well as distributing a fitting profile (we don't have a MS-server), not speaking about Group Policies.

Is there any usable guideline for people like us? Today, each FF-installation looks different and I would like to unify this as easy as possible.

Hi,

I am having the issues on more than 1 pc that after updating the firefox esr 128 version to 140 esr version, the firefox does not work properly, specially with xWiki. when i click on xwiki (on-premis server), i can read the contents and all. but when i click edit then it shows the blank page. this is very odd as it happens after updating to 140 version. picture is attached.

Thanks Sheras

How do I lock the Microsoft Purview settings in the attached image using intune, so users cannot change them.

I have been able to make it that they cant disable or remove the extension but cannot figure out how to make it that they cant change the settings. I did try making a json file but it does not seem like Firefox uses it.

We are allowing end user to scan 2D matrix barcode using a wedge scanner in our application. We are facing a problem where different elements of the bar code are not getting split into the application. On investigating this further, we found that Firefox browser not recognising the FNC character(input character 29) coming from input stream (barcode scanner in this case).

I've been tasked with removing Firefox from all Windows workstations in our enterprise environment. Our users don't have local admin, so when they install Firefox, it is installed in the user's profile.

I've just installed Firefox 143.0.1 in my own user profile for testing purposes. However, when I attempt to uninstall, either from Control Panel or by running %localappdata%\Mozilla Firefox\uninstall\helper.exe manually, UAC prompts for elevation, even though I installed without elevating.

I've dug in a bit more, and I found this was an issue five years ago as well:

https://support.mozilla.org/en-US/questions/1286070

According to that post, the issue was resolved, but it seems to have come back.

Any help would be appreciated.

I have a few questions regarding the auto-update policy of extensions installed via ExtensionSettings with the force_installed installation mode.

1. Can the extension receive auto-updates just like extensions installed through normal means? (e.g. extensions installed from https://addons.mozilla.org)
2. If so, will the user be notified when the extension requests new permissions?

I've been tasked with removing Firefox from all Windows workstations in our enterprise environment. Our users don't have local admin, so when they install Firefox, it is installed in the user's profile.

I've just installed Firefox 143.0.1 in my own user profile for testing purposes. However, when I attempt to uninstall, either from Control Panel or by running %localappdata%\Mozilla Firefox\uninstall\helper.exe manually, UAC prompts for elevation, even though I installed without elevating.

Is this a known issue? If yes, is there a workaround?

Thanks!

We recently update Firefox with version 138.0 and now getting the message "Gah. Your tab just crashed" when opening the browser.

We attempted to update and install version 138.0.1 only resulting with the same error. We also found and attempted the following all resulting with the same error: - change the about:config page for settings to false for both browser.tabs.remote.autostart and browser.tabs.remote.autostart.2

- clear browser cache.

- enable Temporary Mode in the Help menu. This appears to fix the problem but only for the current browser session. When a new Firefox window is opened, the error reappears.

What is needed to resolve this error or is there a way to permanently enable Temporary Mode or some similar setting? Thanks for all your help with this.

Hello, Mozilla community.

I am trying to configure a Firefox ESR installation so that every new user on a computer automatically receives a visual customization (a logo change on about:home) through userChrome.css and userContent.css files.

My goal is to do this without using Group Policy (GPO) or logon scripts, by only modifying the files in the Firefox installation folder.

Environment:

Firefox Version: Firefox ESR 140.3.0esr

Operating System: Windows 11 Pro

Context: Standalone machine, managed without Active Directory.

My Question:

Is this method of deploying a default profile via installation files (defaults/profile or distribution.ini) still supported in recent versions of Firefox ESR?

Is there an additional step or configuration I am missing for Firefox to recognize and use the bundled profile when creating a user's first profile?

Is there any policy in policies.json that could be interfering or that is required to enable this behavior?

Thank you very much for your help and your time.

Hello,

For enterprise solutions, for our browser extension can we disable the switch button where user can turn-off the "Access your data for all websites"?

This can be informed to the end user and also approved by the IT admins.

But the option to disable at runtime on the fly needs to be disabled.

Dear Sir or Madam,

We are experiencing an issue with various users on our terminal servers whereby websites open very slowly when using Firefox. When I access the website using Edge from the same user session, everything works very quickly. We have already tried creating a new profile in Firefox and clearing the cache, but without success. Could you please help us?

The operating system used is Windows Server 2022.

Current version of Firefox has

    (1) popups to get me to download a new version,
    (2) tab pickup,
    (3) popups to show
    article titles,
    (4) popups to show
    current URLs.

I just want to download the install programs until I get the most recent one that has none of (1) - (4).

I need to go back 1, 3, 5, 10 years?

So where on the Internet should I go to get such an old Firefox install program?

I used to really like Firefox, but changes (1) -- (2) have ruined it for me.

I have recently needed to update my motherboard, and the workshop put my C: and D: drives into an old second-hand motherboard they had. I have now checked Firefox - which was on my C: drive, and it works with all my old bookmarks. However I seem to now be part of an 'Enterprise', which I do not want. How do I get rid of my involvement with an Enterprise within Firefox? Thanks for your help. Kanga85

Recently we've began installing Firefox 140.2.0esr to our environment via the .msi file that Mozilla provides, however we're running in to a very odd incident.

After approximately 24 hours from installing Firefox esr to devices, it appears that the application is "updating" to 141.0.3 on the "release" channel. As far as I'm aware, this shouldn't be possible to begin with. But we've applied these settings via GPO:

Computer Config > Policies > Admin Templates > Mozilla > Firefox Application Autoupdate = Disabled Pin updates to a specific version = Enabled = Set to 140.2.0 Background updater = Disabled Disable Update = Enabled Manual Update Only = Enabled

After applying the GPO, confirmed this appears within the registry:

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Mozilla\Firefox\ AppAutoUpdate = 0 AppUpdatePin = 140.2.0 BackgroundAppUpdate = 0 DisableAppUpdate = 1 ManualAppUpdateOnly = 1

At this point, I'm at a loss. We cannot have rapid release be what's installed in our environment. Is there something broken with 140.2.0 or are we doing something wrong here?