Try to delete the file urlclassifier3.sqlite to reset the phishing protection database and force Firefox to rebuild a new database file (this can take some time).<br /> You can find the file urlclassifier3.sqlite in the parent location of the cache.<br /> You can see the location of the cache on the about:cache page via the location bar like you access a website.<br /> XP: C:\Documents and Settings\&lt;user&gt;\Local Settings\Application Data\Mozilla\Firefox\Profiles\&lt;profile&gt;\ *http://kb.mozillazine.org/Profile_folder_-_Firefox ---- Create a new profile as a test to check if your current profile is causing the problems. See "Basic Troubleshooting: Make a new profile": *https://support.mozilla.org/kb/Basic+Troubleshooting#w_8-make-a-new-profile If the new profile works then you can transfer some files from the old profile to that new profile, but be careful not to copy corrupted files. See: *http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox