Hi, If use Windows Os once delete this way after uninstall C:\Users\username\AppData\Local\Mozilla Or you can use CCleaner After, again install

You can check if you can start Firefox in <u>[[Safe Mode|Safe Mode]]</u> by holding down the Shift/Options key. *https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes ---- 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 install 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 Boot the computer in Windows Safe Mode with network support (press F8 on the boot screen) as a test. *http://www.bleepingcomputer.com/tutorials/how-to-start-windows-in-safe-mode/