Firefox 59 does not change UI language

Bug #1755918 reported by Karlchen on 2018-03-14
This bug affects 3 people
Affects Status Importance Assigned to Milestone
firefox (Ubuntu)

Bug Description

Symptom: Since updating to Firefox 59, the Firefox UI items will be English only. E.g. all items under Peferences. Switching from en_US to de does no longer work.

The Firefox packages firefox, firefox-locale-en, firefox-locale-de are installed. All 3 packages have been updated from 58.0.2 to 59.0 by the updater.

When still on Firefox 58.0.2, the following settings existed and made sure my Firefox UI was localied to German (de)
intl.locale.matchOS=true (boolean, default)
general.useragent.locale=de (string, default)

After the update to Firefox 59.0 the second parameter is no longer set. It is simply not present any longer in about:config.
Adding it and restarting Firefox 59 does not have any effect.
The UI will remain English only and the parameter is gone.

This affects both Firefox packages:
firefox 59.0+build5-0ubuntu0.16.04.1
firefox 59.0+build5-0ubuntu0.14.04.1

Ubuntu releases:
Ubuntu 16.04.4 32-bit
Ubuntu 14.04.5 32-bit

Revision history for this message
Karlchen (karlchen) wrote :

Actually, the root cause is something which Mozilla seems to have forgotten implementing in Firefox 59:

Starting with Firefox 59, the parameter which specifies your localized UI language setting is no longer general.useragent.locale, type string, but
intl.locale.requested, type string

Mozilla seems to have forgotten to implement an automatism which rewrites the pre-Firefox parameter
- general.useragent.locale=de # German as an example
+ intl.locale.requested=de

So the solution is adding intl.locale.requested manually in about:config and restarting Firefox 59.0.

This bug report can be closed therefore.

Revision history for this message
Ubuntu Foundations Team Bug Bot (crichton) wrote :

Thank you for taking the time to report this bug and helping to make Ubuntu better. It seems that your bug report is not filed about a specific source package though, rather it is just filed against Ubuntu in general. It is important that bug reports be filed about source packages so that people interested in the package can find the bugs about it. You can find some hints about determining what package your bug might be about at You might also ask for help in the #ubuntu-bugs irc channel on Freenode.

To change the source package that this bug is filed about visit and add the package name in the text box next to the word Package.

[This is an automated message. I apologize if it reached you inappropriately; please just reply to this message indicating so.]

tags: added: bot-comment
affects: ubuntu → firefox (Ubuntu)
Revision history for this message
Launchpad Janitor (janitor) wrote :

Status changed to 'Confirmed' because the bug affects multiple users.

Changed in firefox (Ubuntu):
status: New → Confirmed
Revision history for this message
Mantas Kriaučiūnas (mantas) wrote :

Problem is, that some systems with ubuntu-defaults-it , ubuntu-defaults-zh-cn and ubuntu-defaults-baltix packages installed doesn't have line
in /usr/lib/firefox/distribution/distribution.ini

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