User Agent: Mozilla/5.0 (Windows NT 6.1; Trident/7.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; .NET4.0C; .NET4.0E; Tablet PC 2.0; rv:11.0) like Gecko Steps to reproduce: Sometimes when I start Firefox it will work for a few minutes and then it fails to connect to the Internet. If I close Firefox and try to restart it says Firefox is already running. Actual results: Firefox attempts to load a page but never does. If I restart I get an error. After a few minutes from when the problem begins a crash dialog comes up. It says the bug report has successfully been sent. Expected results: It should load pages normally. IE will load pages, but I can't use IE. Everything in IE is difficult to use.

Can you please try the refresh Firefox feature ? https://support.mozilla.org/en-US/kb/refresh-firefox-reset-add-ons-and-settings Do you use a third-party Firewall or security software that intercepts Firefox network connections ?

I will try the refresh feature as soon as Firefox quits working. At present it is working correctly. I use Microsoft Security Essentials. I don't know if this would have anything to do with it. I have used MSE for a few years without any problem from FireFox.

Firefox just quit working again. I have done the refresh. It may not be a Firefox problem because Windows Media Player will not start at the same time as Firefox will not start. If I reboot then everything works normally again. I haven't noticed any other programs not working. I also ran SpinRite on the harddrive, but that didn't seem to help.

Firefox stopped working again. Windows Media Player still works. I have just uploaded another dialog I get after clicking Cancel on the "Firefox is already running" dialog. The last two times it quit working I had left the computer for a couple of hours. Firefox was closed before I left.

There is nothing that I can suggest now because i can not reproduce the issue and I'm out of ideas :-( I could check the crash report but I doubt it helps much. Please provide the crash id from about:crashes : https://developer.mozilla.org/en-US/docs/How_to_get_a_stacktrace_for_a_bug_report#How_to_get_a_crash_ID_with_the_Mozilla_Crash_Reporter

d8c1e4aa-f771-47b4-b0d8-578352150305

Maybe Patrick has an idea but I doubt it because we can not reproduce this issue.

The "won't connect" part is interesting. We again hang in nsUDPSocket::OnSocketDetached|PR_Close according comment 7. Seems like it takes a really long time... Definitely a duplicate of bug 1124880.

yes - its not certain that the udp is at the root of all hangs associated with 1124880, but this one definitely is. dcox21 - thank you for reporting it in detail!

I realize this is marked RESOLVED as DUPLICATE, but this is the exact behavior I am seeing. FF will spin on loading a new page and never actually load it, or any others I try. Then, when I try and restart it, I get the same issue mentioned above and cannot start unless I delete my profile and start with a new one. I believe I've also seen it happen in with all plugins disabled? Here is a crash report: https://crash-stats.mozilla.com/report/index/0c321c1a-184d-40d7-b13f-bec4f2150317 Is it certain that the first part of this behavior is covered by bug 1124880? If not, is there anything I could do to help track it down? I've had to switch browsers, but I'd like to switch back to FF.

My symptoms were exactly as described in this bug and the work-around I posted in bug 1124880 comment 35 has gotten rid of them all. I believe it's correctly dup'd.