After Firefox upgraded to version 47.0.0 (and also 47.0.1) on OS X, Firefox no longer fills in password fields for me. It does fill in other autocomplete values, but not the password field of any websites. It also does not prompt me for my master password at any point (except when I view saved passwords in Preferences, Security). It also does not prompt me to save new passwords. This is what I have tried: - I have checked that signon.autofillForms is at its default value of true. - I have tried launching Firefox in Safe Mode. I had installed and uninstalled LastPass in the past, but I presume launching Firefox in Safe Mode would be enough to workaround any issues LastPass may have caused. - I have checked that the passwords are still there by going to Preferences, Security. - I have made sure that the option "Always use private browsing mode" has not been enabled in Preferences, Privacy.