Hi jean-yves.vautrin, please ignore the spam message with a phone number -- that's not official and we don't know what they will do to your system if you engage.

Hello,

Remove The Browser Completely from your System and do a fresh install, It will work.

https://www.mozilla.org/en-US/firefox/new/

Thank You.

I did it. Doesn't work

Hi jean-yves.vautrin, sometimes a firewall or other security program will prevent the small "online" installer from downloading additional files for installation. In that case, you can use the larger "full" or "offline" installer instead. On the following page, please use the selectors to change the automatically detected system type and language to fit your needs:

https://www.mozilla.org/en-US/firefox/all/#product-desktop-release

Does that installer work on your computer?

hello jean-yves.vautrin,

follow the steps and given link your problem easy to fixed.

[https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-d...]

Please make sure there are no instances of Firefox running in the Task manager. Then please run this :

[https://www.revouninstaller.com/revo_uninstaller_free_download.html] If it does not find anything please go through your drive C: and Delete all Mozilla folders. Install from here :

[https://www.mozilla.org/firefox/all/] Turn of your Firewall or A/V for the install. Have a scan by [https://www.malwarebytes.com/] also.

Please let us know if this solved your issue or if need further assistance.

Thank you Asked Question in Mozilla.

Regards,

Arman

Hi Arman, if you recommend to someone to delete their entire Mozilla folder, you need to warn them to back up their data (bookmarks, saved logins, etc.) first. Otherwise, you may be creating a bigger problem than they started with.

Ref. Back up and restore information in Firefox profiles

Hi Harman,

I also deleted the folder C:\Users\PC-JY\AppData\Roaming\Mozilla.

Without sucess.

Of course, bookmarks, and profiles have been backup with Acronis True Image (every day and every month).

Regards,

JY V