What kind of issues do you have that you want to start Firefox in Safe Mode? Can't you start Firefox at all? It is possible that your security software (firewall, anti-virus) blocks or restricts Firefox or the plugin-container process without informing you, possibly after detecting changes (update) to the Firefox program. Remove all rules for Firefox and the plugin-container from the permissions list in the firewall and let your firewall ask again for permission to get full, unrestricted, access to internet for Firefox and the plugin-container process and the updater process. See: *https://support.mozilla.org/kb/Server+not+found *https://support.mozilla.org/kb/Firewalls *https://support.mozilla.org/kb/fix-problems-connecting-websites-after-updating ----- There are other things that need your attention. Note that your System Details List shows multiple Flash plugins. # Shockwave Flash 13.0 r0 # Shockwave Flash 12.0 r0 You can find the installation path of all plugins on the <b>about:plugins</b> page. *http://kb.mozillazine.org/Issues_related_to_plugins#Identifying_installed_plugins You can check the Flash player installation folder for multiple Flash player plugins and remove older version(s) of the plugin (NPSWF32) and possibly (re)install the latest Flash player. *(32 bit Windows) C:\Windows\System32\Macromed\Flash\ *(64 bit Windows) C:\Windows\SysWOW64\Macromed\Flash\

please continue in your original thread: https://support.mozilla.org/questions/996546