Does the icon show up on the Task Bar? ------------ Some problems occur when your Internet security program was set to trust the previous version of Firefox, but no longer recognizes your updated version as trusted. Now how to fix the problem: To allow Firefox to connect to the Internet again; * Make sure your Internet security software is up-to-date (i.e. you are running the latest version). * Remove Firefox from your program's list of trusted or recognized programs. For detailed instructions, see '''[https://support.mozilla.org/en-US/kb/configure-firewalls-so-firefox-can-access-internet Configure firewalls so that Firefox can access the Internet.]''' {web link} ------------------ You may have corrupt '''xulstore.json''' or '''Localstore.rdf''' file. '''Close Firefox'''. Open your file browser to this hidden location: * Mac: *~/Library/Application Support/Firefox/ * Linux: *~/.mozilla/firefox/ * Windows: %AppData%\Mozilla\Firefox\ * *C:\Users\<user>\AppData\Roaming\Mozilla\Firefox\ Locate the above files. Then rename or delete them. Restart Firefox.