[FullRangeMan]

I made a mistake deleted the extension.ui.locale command line in the FF 62 about:config file.

How I include a new line to type this command?

There is no New option on the right click mouse.

[WGH]

Download a fresh copy of 62.0.3 and re-install.

[srb]

There is no delete function in the about:config webpage, so if you somehow deleted a preference line item, did you directly edit the prefs.js file?

You can create a new entry on the about:config webpage by right-clicking in the preferences window and
1. select  New > Boolean
2. enter the preference name extensions.ui.locale.hidden 
3. select the Boolean value  True  or  False

If you're directly editing the prefs.js file the line to add (if missing) is
user_pref("extensions.ui.locale.hidden", true);

[FullRangeMan]

OK, just fix it. It need type the command in the comand line first and after click new.

Thanks guys

[Big Red Machine]

Thank goodness it's fixed because I had no bleeping idea what you guys were talking about

[WGH]

I knew there was an easier fix than just re-installing but it was late. Steve always has the right answer 

[FullRangeMan]

I was trying to change the FF language, in the v62 Mozilla modify it to the local language, no success yet.
Lasts try was:
menu/options
and
extensions.ui.locale.requested
and
extensions.ui.locale.requested=en at prefs.js
Any idea? Mozilla help is useless.

[srb]

To enable a language in Firefox prefs.js, you must first download and install the relevant language pack. 

Is this the procedure you're following?

https://support.mozilla.org/en-US/kb/use-firefox-interface-other-languages-language-pack#w_how-to-manage-language-packs

[FullRangeMan]

Yes this is it. I even removed the other languages I had to force it assume english but it dont work, FF v62 always assume the ip location or W10 location info.