Are you using any password add-ons/programs?

Type about:preferences#security<enter> in the address bar. Look under Logins,

Note: For Firefox v56+ its; about:preferences#privacy Look under Forms & Passwords +++++++++++++++++++++++++++++++ Turn on Remember Logins. To check the passwords you have listed, press Saved Logins.

If the above does not help, Start Firefox in Safe Mode {web link}

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

You can check this pref on the about:config page to see whether it is locked to true.

• pref.privacy.disable_button.view_passwords

You can open the about:config page via the location/address bar. You can accept the warning and click "I accept the risk!" to continue.

• http://kb.mozillazine.org/about:config

Neither of these work. Remember logins is checked and I can open Exceptions. But Saved Logins is greyed out. And about:config is locked at true.

pref.privacy.disable_button.view_passwords;true

I've tried opening in safe mode. I guess I could just do a full refresh and go back to default. Sad face.

A refresh won't help in this case. You have some (security) software that has locked this pref and possibly other settings.

You can check if there are .js files like autoconfig.js present in the "defaults\pref" folder in the Firefox program folder. The channel-prefs.js file that sets app.update.channel is legitimate. You can open this other file in a plain text editor like Notepad (Mac: TextEdit) and please post its content to see whether that allows to identify what software created the file. Also please post the content of the autoconfig.cfg file referenced in the .js file.

See also:

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

If you find a .js file if defaults\pref and a corresponding .cfg file in the main Firefox program folder then do a clean reinstall and delete the Firefox program folder.

Try this:

• download the Firefox installer and save the file to the desktop
  *https://www.mozilla.org/en-US/firefox/all/
• start the installation with a double-click on the desktop icon

Make that the Firefox program folder is deleted before you reinstall Firefox