Since when I upgraded ML to Mavericks Safari is no longer able to log me into Facebook. When I go to the login page it suggests me the correct credentials, I hit the Login button, the page refreshes but nothing happens, like if the credentials where empty. Firefox works perfectly, I even logged out and back in to make sure the credentials are the same that Safari suggests, and so they are. Needless to say for a different user on the same Mavericks Safari logs in correctly.

The same happens with most web pages that need a login, web mails for instances, I have tow accounts on different webmail providers and none of them works. Of course using the same mail services with POP3 works fine. Even on this very site I cannot post a thing with Safari, I'm going to switch to Firefox to be able to post this question. Again, Firefox or a different user are OK.

Do you have any idea/suggestion?