Since Firefox 41 it's no longer possible to customize the page shown in a new tab via changing the preference 'browser.newtab.url' in about.config. Because of the fact that hijackers abused the preference in the past, Mozilla decided to remove it.

Why won't you update, so you can use the New Tab Override add-on  ?

https://addons.mozilla.org/en-US/firefox/addon/new-tab-override/ (Webextension)

MFSebamo said

My new tab recently changed, but I liked the default one.

What did it change to? Might help us determine what changed the UR L, which isn't supposed to be possible any longer.

Try the Firefox version from the official Mozilla server if you currently use a version from the repositories of your Linux distribution.

You can find the full version of the current Firefox release (56.0) in all languages and all operating systems here:

• https://www.mozilla.org/en-US/firefox/all/
• https://www.mozilla.org/en-US/firefox/notes/

Enigma said

Why won't you update, so you can use the New Tab Override add-on  ?

Installed newest update, nothing changed.

the-edmeister said

What did it change to?

It changed to some kind of search engine, here's the exact url : "http://search.hemailaccessonline.com/?uid=c124e7c2-d221-4338-8a1c-958ec6e9fbd8&uc=20171006&ap=appfocus1&source=googledisplay-googledisplay-v3&page=newtab&implementation_id=email_4.0.17"

cor-el said

Try the Firefox version from the official Mozilla server if you currently use a version from the repositories of your Linux distribution.

I tried, installed the right one through your link, but once again nothing has changed...

A good thing 'the-edmeister' asked that question, cause now we know that you've got malware. That search.hemailaccessonline.com is a browser hijacker, that you of course will need to get rid of.

Go to the 3-bar menu (or   'Tools') => Addons => Extensions and look for any unfamiliar or suspicious looking extensions. When you find any : remove them.

However :   most malware will be 'hiding' somewhere , so let's run malware scans :

Further information can be found in this article :
https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-caused-malware?cache=no

Run most or all of the listed malware scanners.
They all work differently   -   what one program doesn't pick up, the other might.

Also see : https://malwaretips.com/blogs/remove-search-hemailaccessonline-com/

I agree with Enigma. In past threads, users whose unwanted page ended with something like "id=email_4.0.17" had an unknown extension with a name very similar to that, although of course they may change it to something else to evade detection.

The key thing to remember when you open the Add-ons page and click Extensions in the left column, is: what you see on the right side does NOT include extensions that Firefox installs on its own. Everything listed here is your choice (and your responsibility) to manage. So don't assume anything is innocent; be skeptical!

Thank you so much all of you, it was very easy to find the extension, the only one I never put on there, and everything is back to normal !