Start Firefox in Safe Mode {web link}

A small dialog should appear. Click Start In Safe Mode (not Refresh). Is the problem still there?

To reset the search engines, remove these files in the Firefox profile folder;

search.json.mozlz4 ==only== (v45+)

New files are created when needed.

Something else to try:

See if you can use the [Restore Default Search Engines] button at the bottom of the Search panel, to bring back Google and other missing search engines. Read this article for details:

• Change your default search settings in Firefox

Hi AliceWyman and FredMcD,

Thanks for your help. I tried all you recommended me to do, but the problem is still there. Anything else to try, please ?

So deleting sessionstore.jsonlz4 with Firefox closed didn't have effect ?

Do you see all default search engines listed on the "Help -> Troubleshooting Information" (about:support) page ?

You can create a new profile as a quick test to see if your current profile is causing the problem.

See "Creating a profile":

• https://support.mozilla.org/en-US/kb/profile-manager-create-remove-switch-firefox-profiles

If the new profile works then you can transfer files from a previously used profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over problems.

• https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile

Here is the image you attached to your original post:

Can you translate what it says at the very top, next to the info icon ? Does it say something similar to your settings being controlled by your organization?

P.S. If the message at the top of the Options page is similar to "Your browser is being managed by your organization", click on the message (it should be a link) to see what information is given. Someone else (cor-el?) might be able to help you more but you can look at the following pages for possible solutions:

https://support.mozilla.org/en-US/questions/1281644 'Your Browser Is Being Managed By Your Organization'-Issue Resolved

https://support.mozilla.org/en-US/questions/1264369 "Your browser is being managed by your organisation.". Suddenly appeared. What does this mean?

https://techdows.com/2019/06/fix-firefox-says-your-browser-is-being-managed-by-your-organization.html

https://www.askvg.com/fix-your-organization-has-disabled-the-ability-to-change-some-options-in-mozilla-firefox/

Yes, the "Votre navigateur est géré par votre organisation." message means "Your browser is being managed by your organization.". So GPO or policies are active that might affect the search engines. If all search engines are gone then I would expect malware.

• https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-caused-malware

See also:

• https://support.mozilla.org/en-US/kb/customizing-firefox-using-group-policy
• https://support.mozilla.org/en-US/kb/customizing-firefox-using-policiesjson
• https://support.mozilla.org/en-US/kb/customizing-firefox-using-autoconfig

• https://github.com/mozilla/policy-templates/blob/master/README.md