Have you tried Safe mode: Diagnose Firefox issues using Troubleshoot Mode Firefox can't load websites but other browsers can

I will try safe mode if the problem recurs. But I am not sure that that will be a good test. This problem began a week ago, and it has happened four times since last Friday morning. When the problem happens, I cannot trace it to a particular URL, as Firefox is running normally before the problem happens. When the problem happens, I notice is when I either try to open a new tab or go to an existing tab that I had not opened since the last Firefox restart. When the problem occurs, nothing will load - new URLS nor existing tabs, even those that I have viewed since the last restart. And once the problem starts, it is permanent, as I have left Firefox in that state for many hours. I assume that when Firefox is in this state, it is not producing any Internet activity. I have not run a Wireshark trace to prove this.

I do not know how to reproduce the problem, and I assume that it will recur sometime, I just do not know when. So, running in safe mode without the problem recurring will not be proof that any add-on is causing the problem.

--Barry Finkel

hello, i'd try to reset those custom preferences that you have in your profile:

network.http.max-connections: 48
network.http.max-connections-per-server: 16
network.http.max-persistent-connections-per-proxy: 16
network.http.max-persistent-connections-per-server: 8
network.http.pipelining.maxrequests: 8
network.http.request.max-start-delay: 0

I am confused by your response, where you say, "hello, i'd try to reset those custom preferences that you have in your profile:" I checked about:config, and those are the values I have for those six parameters. If I remember correctly, I have not modified any of those parameters. If you want me to change any values, to what values should I set each?

Also, yesterday morning Firefox hung with the same symptoms, so I restarted it in safe mode. If, in safe mode, the problem recurs, what diagnostics should I gather to diagnose the problem? Thanks.

--Barry Finkel

in order to turn back the values in about:config to their originals, please right-click and reset the mentioned settings.

I right-clicked and clicked "reset". Here are the resulting values:

network.http.max-connections: 48 ==> 256 network.http.max-connections-per-server: 16 ==> blank network.http.max-persistent-connections-per-proxy: 16 ==> 32 network.http.max-persistent-connections-per-server: 8 ==> 6 network.http.pipelining.maxrequests: 8 ==> 32 network.http.request.max-start-delay: 0 ==> 10

Is "network.http.max-connections-per-server" supposed to be an integer or a string. It is now a blank string after the reset operation.

Are these changes effective immediately, or do i have to restart Firefox? Thanks.

--Barry Finkel

yes, please restart firefox once after that and try again afterwards please. (network.http.max-connections-per-server isn't supposed to be there by default at all)

You can leave the network.http.max-connections: 48 value if you like in case you would dealt with servers that do not like a larger amount of connection (there was recently a thread with this issue).

I restarted Firefox into safe mode (it appears that in safe mode, Firefox does not honor my setting to "restore the previous session" automatically), and it ran fine for two days. This morning it got into its "not loading" state again. I took a dump via the task manager, and I clicked "Exit" on one of the Firefox windows. All of the Firefox windows closed, but, as before, firefox.exe was still running, and the I/O counts were increasing. I cancelled firefox.exe via the task manager. Would there be anything in the dump that would let us know what is happening? If not, then what other diagnostic technique(s) do I use when Firefox gets into this state? Thanks.

--Barry Finkel