C:\Program Files (x86)\Mozilla Firefox

C:\Program Files (x86)\Fx43

C:\Program Files\Mozilla Firefox

C:\Program Files\Fx43

Did this problem just start? It seems that you have the Websense Endpoint security software installed. From time to time, a Websense update or a Firefox update results in a severe incompatibility. If Websense is an unchangeable feature of your environment -- you can't update or disable it -- or if updating doesn't help, then you might want to try switching to the Extended Support Release version of Firefox (ESR). This is derived from Firefox 38 and while it will get security updates over the next several months, it will not get new features. Websense supports Firefox 38. If you decide to switch, here is how I suggest installing it: '''Clean Reinstall''' We use this name, but it's not about removing your settings, it's about making sure the program files are clean (no inconsistent, corrupted, or alien code files). As described below, this process does not disturb your existing settings. Do NOT uninstall Firefox, that's not needed. (A) Download a fresh installer for Firefox 38.5.2esr from https://www.mozilla.org/firefox/organizations/all/ to a convenient location. (Scroll down to your preferred language.) (B) Exit out of Firefox (if applicable). (C) Rename the program folder, either: ''(64-bit Windows folder names)'' C:\Program Files (x86)\Mozilla Firefox to C:\Program Files (x86)\Fx43 ''(32-bit Windows folder names)'' C:\Program Files\Mozilla Firefox to C:\Program Files\Fx43 (D) Run the installer you downloaded in (A). It should automatically connect to your existing settings. ''Note:'' Some plugins may exist only in that old folder. If something essential is missing, look in these folders: * \Fx43\Plugins * \Fx43\browser\plugins