Firefox Community Forum

Fix for RangeError: invalid language tag and client-side exceptions in Firefox on Linux

Hi everyone, I was experiencing persistent JavaScript errors in Firefox on Linux when loading certain modern websites (e.g., built with React or Next.js). The browser console showed messages like:

   RangeError: invalid language tag: "chrome://global/locale/intl.properties"

   A client-side exception has occurred (see the browser console for more information)
   React error #418 with minified stack traces

This happened even in Safe Mode, with all extensions disabled, cookies/cache cleared, and Enhanced Tracking Protection off. ✅ Root cause and fix:

Turns out the issue was related to missing or broken locale configuration in Firefox. To fix it:

   Open about:config

   Create a new string entry:

       Name: intl.locale.requested

       Value: en-US (or fr, en-GB, etc. — any valid locale)

   Restart Firefox

After adding this key, all affected pages started working correctly. The invalid "chrome://global/locale/intl.properties" error in intl.accept_languages disappeared as well — it seems that was just a side effect of the missing locale setting. 🔁 Summary:

If you’re seeing RangeError: invalid language tag and React crashes, try adding intl.locale.requested manually. This fixed the issue entirely for me on Linux.

Hope this helps others!

Hi all, I'm using Firefox 140.0.4 (64-bit) on Debian Trixie and I'm getting a weird behavior with the auto-complete functionality of the address bar.

If I type the first character the address gets auto filled (see 20250711_First-character-auto-fill-working.png attachment), then if I type the second character the auto filled result disappears (see 20250711_Second-character-auto-fill-NOT-working.png).

I've tried any search option combination, but results doesn't change. At the moment I'm using for the address bar just "Browsing history" (see 20250711_Address-bar-settings.png).

The correct behavior would be, as in the past, that new characters confirming the address would leave things as they are. Do you have any suggestion on how to restore the original behavior?

Many thanks,

Raoul

Hi Team, I am using Linux Mint 20 Cinnamon. Cinnamon version is 4.6.6. The issue is that I was browsing and by mistake I selected one tab then dragged it for sometime and then released the tab but that created a new window and now the old windows are not visible in ALT + Tab function. The windows are showing in the Firefox task manager and also the box icon in the top right corner in that "open tabs". Now I am not able to even change the window or able to access the opened tabs. Attached the screenshot and as you can see in that there are total 4 windows showing in firefox and one as active but in the bottom on the firefox icon you can see its only 1 window. How can I access the remaining 3 windows? Found one ticket (https://support.mozilla.org/en-US/questions/1477845) in this the recommend solution does not work. When I try to click on the window 1 tabs then I do not get any response. I tried both the solution but none worked.

Thanks for the help in advance. @Mozilla team member is seeing please check and fix this bug if possible.

All of a sudden Firefox started to use alt+number (e.g. alt+3) to switch to that tab (i.e. tab 3 in my example).

Why? How do I disable this? It prevents me from typing any of the special characters that are located on alt + any number key. E.g. I can type the at-sign, not the dollar, or any such character which requires the alt-modifier and a number.

I'm trying to access my federal government account. They want me to verify my identity at verify.id.me. When I reach the point that it wants to see my ugly mug on camera it tells me there is no camera. I've given verify.id.me permission to use the camera in privacy & security. I can record a video with ffmpeg. What have I missed? I don't see any relevant errors in firefox's output. I'm trying in safe mode.

latest versions of firefox (now at 140.0.1) keeps opening onto my 2nd monitor which is off - how to stop it doing it. Tried making new profile which works for awhile, but sooner or later they all bump it to the 2nd monitor and it never comes back - tried moving to primary and closing it there, but next time back on #2. Open 2nd window while first is on primary, and that goes to 2nd monitor...

I spend a lot of time opening a link in a new tab, and then once I have finished looking at it I need to move my mouse pointer over to the tab to close it so that I can go back to my main page.

I would like a simple addition to the Firefox code that would allow me to close the current tab with a double click anywhere on the current tab. This should be a simple thing to implement in a Firefox release.

Thanks

hello. i downloaded firefox from official void linux repo, and have issue with font rendering or smth. in settings option "Allow pages to choose their own fonts, instead of your selections above" is enabled. don't have same issue in any other gtk apps on my system.

Does anybody know how to take screenshots from the Firefox "chrome" context like so: ```js const { GeckoDriver } = ChromeUtils.importESModule(

   "chrome://remote/content/marionette/driver.sys.mjs"

); const image = await GeckoDriver.prototype.takeScreenshot(); ```

The error I get is: "Browsing context has been discarded".

I'm rewriting the text-based browser https://brow.sh and have already been successfully using the screenshotter from the Web Extensions API. And of course I know that I can take screenshots directly from Webdriver (namely GeckoDriver in the case of Firefox), but they're just too slow, having to send the screenshot to Webdriver and then back to the web extension. So there are 2 reasons I'd like screenshots from the chrome context:

1. It'd save me having to manage the Browsh web extension. Having to have both a separate build process and the dedicated signed publishing process isn't fun. 2. The current version of Browsh only renders the "content" context of the browser, which is arguably the most important part I know, but it'd be nice if Browsh could also render things like the permissions dialog, URL history suggestions, etc.

So any other ideas that could address one or both of those points would be much appreciated.

When I log in to my account at https://my.noip.com/ and display my dashboard there is a constantly displayed banner across the top of the page that says:

FireFox prevented this page from automatically reloading - Allow

when I click Allow the page just reloads with the same banner

What setting can I change to get rid of this banner?

I am trying to set up an MMDVM Pi-Star DMR Hotspot for Amateur Radio. The address for the device is http://pi-star. What do I need to do to get https-only mode 100% disabled? The device that I am trying to set up is: Radioddity RHS-H1 MMDVM Hotspot | OLED Screen | Raspberry Pi-Zero W | Support P25/DMR/D-STAR/YSF/NXDN | UHF VHF WiFi Digital Voice Modem | 16G TF Card

I am using Firefox version 140.0.2 on PCLinucOS Debian (Bookworm) Edition.

Hello, after a power cut I lost all my bookmarks. When I try "Manage Bookmarks -> Import and Backup -> Restore -> Choose File..." nothing happens.

In the folder ".mozilla/firefox/6924v31j.default-1728390329118/bookmarkbackups" there are several backup files, but the newest has the date Jun 25, though the name suggests it's from Jul 2: -rw-r--r-- 23850 Jun 25 13:07 'bookmarks-2025-07-02_184_mg1znof1NbBiyJ14ZcO9SluvTvLZI-rxPSm20YZUJww=.jsonlz4'

In the directory ".mozilla/firefox/6924v31j.default-1728390329118" there is also places.sqlite from Jul 4 11:59 (that was the moment when the power was cut).

How can I restore my bookmarks?

I have Firefox on 4 separate devices (Windows 10, Windows 11, Linux Ubuntu derivative x 2).

For the last 2 weeks, every time I open Firefox, the recommended stories are active. I go into settings, turn off the setting and it behaves correctly for that session. However, when I open Firefox on a different device, or the next time, recommended stories are showing once again. I like and want a clean, minimalist interface, and expect Firefox to honour my settings.

Thank you.