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

Note: Some software, like Advanced SystemCare with Surfing Protection, can protect files in the Firefox profile folder against changes. If you have such software then check the settings or uninstall this software.

Are you using a password add-on?

I am not using Advanced SystemCare neither software with Surfing Protection nor any password add-on.

Advanced SystemCare is an example.

Start Firefox in Safe Mode {web link} by holding down the <Shift> (Mac=Options) key, and then starting Firefox.

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

I started Firefox in Safe Mode but the problem is still there. It does not remember any password (for instance Gmail; Amazon and not even Forefox´s sync password (I have to reconnect each time). The problem is with w7. On Mac everything is working fine.

juangrandal said

The problem is with w7

If you think so, you should also ask your question here;

https://support.microsoft.com

http://answers.microsoft.com/en-US/windows/forum/windows_10

Start your Computer in safe mode with network support. Then start Firefox. Try Safe websites. Is the problem still there?

http://encyclopedia2.thefreedictionary.com/Linux+Safe+Mode Starting Any Computer In Safe Mode; Free Online Encyclopedia

Refresh was the solution

That was very good work. Well done.