This morning, I received a Firefox message indicating that a new version (33.1) of Firefox was available -- I accordingly accepted the auto-update. Since the update, I find that Firefox can no longer connect to the internet. Suspecting a Firewall issue, I disabled Symantec Endpoint firewall, and found that Firefox suddenly worked again. Since this is a work PC, I am bound to keep the firewall activated (and I wish to do so anyway). Symantec does not seem to have any capacity to add individual programs as exceptions. One has the option to allow all IP traffic, or just application IP traffic. Is the new Firefox simply incompatible with Symantec Endpoint? Why would the version that I had (33.0.3 if i am not mistaken) have worked without problem? As a further detail, I should add that when I click on the Extension/Add-on manager in Firefox, I see that Symantec Vulnerability Protection 12.3.0.3 -1 is incompatible with Firefox 33.1; I assume that this is part of the problem? (And if so, should I contact Symantec?)