Hello serman77, check IF you have in your profile folder a User.js file.

The user.js file does not exist by default. If you create the file, forget it, if you have not create the file then delete the User.js file, to see if the problem goes away (some programs create and write in the file also).

If you have not a user.js file then see : Corrupt or damaged prefs.js file

thank you

Thank you Ideato! I have however tried all your options, but this auto chosen "system settings" in the proxy menu continues to proceed. Also, all pages low more slower, so I wonder what kind of settings these are!

Is there anyway to reveal what kind of system settings Firefox applies for the proxy? Note: This is coupled with the same effect in IE and Chrome on the same computer. They all have this locked proxy selection to System Settings.

Check if your security software (firewall, anti-virus) is the problem.

Open the computers network settings and check them.

If your firewall (security software) is monitoring internet connections then that software might be responsible for resetting this pref to the default to use the system proxy. So you can check the advanced settings in your firewall for Firefox.

See also:

• http://kb.mozillazine.org/Preferences_not_saved

Thanks. I use ADAware, which has network monitoring activated, including webprotection. However, when I deactivate it, it sill selects the same System Settings for Proxy.

I installed Anti malware bytes and scanned the system. The result was that this auto-proxy setting is now solved.

Hello,

I am glad to hear that your problem has been resolved. If you haven't already, please select the answer that solves the problem. This will help other users with similar problems find the solution more easily.

Thank you for contacting Mozilla Support.