A possible cause is security software (firewall,anti-virus) that 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

• http://kb.mozillazine.org/Browser_will_not_start_up

I Posted this for a Mate, The problem is now solved. He had to use the shortcut ( Win Logo + Direction Up key ) to expand Firefox from the Icon on the Task Bar. He verified the Properties screen resolution was set to Maximze before. We checked everyone's lisr for a possible solution, Thanks for the Support Mozilla and Members ^_^

Hi, I am having a problem with firefox opening. I have the icon on my toolbar, but when I click to open, It highlights and gets the little whirly thing which is indicative of it going to open but it quickly stops and nothing happens. I tried rebooting, nothing happened. I reinstalled began working - left computer on went to bed, not working. Took to my computer tech, who uninstalled and then reinstalled the latest version - brought computer home hooked it all up and working, been away today, daughter used firefox to access facebook and had no problems, I came home and now again not working. Computer Tech fella, will look at it again but suggested that I post problem in here and see if there is something with the latest update - as when I get update notices I usually do the upgrade. Any suggestions. I am not new to firefox have had it for several years and this is the first weird problem that I have had.