Hello extraprase,

Hoping that I'm not misconstruing your question - would you please take a look at this article :

https://support.mozilla.org/en-US/kb/how-to-fix-preferences-wont-save

Does that help  ?

well a bit too much information for me. what I tried to avoid any potential bugs and corrupt files, I removed the program from my computer and downloaded and installed it again. It did succeed however whilst installing this showed up. (tried twice with same experience) no idea what´s up with that. will try using it and see if the settings stay (it´s basic settings like what opens after new launch, default search engine..)

I got the feeling that you did not install Firefox from here (which you should do) :

https://www.mozilla.org/firefox/all/

(and choose your preferred language)

Then re that screenshot you provided - would you take a look at this please :

https://www.thewindowsclub.com/microsoft-register-server-stopped-working-windows

here I downloaded it from https://www.mozilla.org/en-GB/

extraprase said

here I downloaded it from https://www.mozilla.org/en-GB/

Nothing wrong with that ......

Did you follow the steps in the article I gave you a link to  ?

I´m affraid it´s a bit too complicated to understand it.

Anyways I´ve reinstalled it again and it happened again. Interesting for me was that after the fresh install the default search engine was Google so I let that setting be but after changing the other settings and relaunching it it appeared with Bing...

extraprase said

Anyways I´ve reinstalled it again and it happened again.

What happened again  ? As shown in your screenshot  ?

Interesting for me was that after the fresh install the default search engine was Google so I let that setting be but after changing the other settings and relaunching it it appeared with Bing...

"after changing the other settings" ......

What settings did you change  ?

I'm not sure if this is what you should check, but giving you this to take a look at :

https://support.mozilla.org/en-US/kb/change-your-default-search-settings-firefox

and :

https://support.mozilla.org/en-US/kb/add-or-remove-search-engine-firefox

I changed to open in the sessions where I ended last time, made sure the default search engine is Google and to always ask where to save downloaded files.

extraprase said

I changed to open in the sessions where I ended last time, made sure the default search engine is Google and to always ask where to save downloaded files.

If those preferences won't save, I can't think of anything else right now than to ask you once again to read this article :

https://support.mozilla.org/en-US/kb/how-to-fix-preferences-wont-save