I have latest version of FF and MacBook Pro 10.9.2. Recently had major keychain problems and worked a lot with Apple to solve them. Now all is well but…. I am now frequently asked to enter my master password when I am in FF; they has never happened before. For example, when I go to Amazon, a window opens asking for the master pw. In some cases, this is not a big deal because I can cancel the request and my keychain will get me into the site. In other cases, my keychain does not work if I cancel the request for the MPW and I have to enter my access information. I asked Apple support about this, and they said to contact you.